DIS2022: XXIX International Workshop on Deep-Inelastic Scattering and Related Subjects

2 May 2022, 08:00 → 6 May 2022, 20:00 Europe/Madrid

Nestor Armesto Perez (Universidade de Santiago de Compostela (ES))

DIS2022 is the 29th in the series of annual workshops on Deep-Inelastic Scattering (DIS) and Related Subjects. The conference covers a large spectrum of topics in high energy physics. A significant part of the program is devoted to the most recent results from large experiments at BNL, CERN, DESY, FNAL, JLab and KEK. Theoretical advances are included as well. The last four editions were in Stony Brook in 2021 (virtual), Torino in 2019, Kobe in 2018 and Birmingham in 2017; a full list of previous editions can be found here.

We plan to hold the conference in person in Santiago de Compostela. The registration fee is 430 EUR until April 8th 2022 (NEW), and 500 EUR thereafter. Those who cannot attend in person because their institutions or countries do not allow the travel, because they do not comply with the COVID-related requirements to enter Spain, or because of medical reasons, are invited to contact us at dis2022-registration@igfae.usc.es.

If the conference has to be moved online due to unforeseen circumstances, a refund (minus bank transfer expenses) down to a smaller online fee will be done.

Sponsors:

 

 

 

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Also sponsored by Brookhaven National Laboratory BNL, Deutsches Elektronen-Synchrotron DESY, the European Organization for Nuclear Research CERN, and Thomas Jefferson National Accelerator Facility JLab.

Final Bulletin.pdf

PCR_and_other_COVID_tests.pdf

Monday 2 May

08:30 → 09:10 Registration

09:10 → 11:00 Plenary sessions: Plenary 1

Convener: Fred Olness (Southern Methodist University (US))

09:10 Welcome by the Vice-chancellor for Scientific Policy of the USC

Speaker: Vicente Pérez Muñuzuri (Universidade de Santtiago de Compostela)

09:20 Welcome from the organisation

Speaker: Nestor Armesto Perez (Universidade de Santiago de Compostela (ES))

Presentation_020522.pdf

09:30 Recent progresses on determination of PDFs

Speaker: Jun Gao (Shanghai Jiao Tong University)

DIS2022_JunGao_v2.pdf

10:00 How small is small x? A perspective from the NLO CGC phenomenologyv

Speaker: Bowen Xiao (The Chinese University of Hong Kong (SZ))

DIS-2022-Xiao.pdf

10:30 What we all should know about ultraperipheral collisions

Speaker: Peter Alan Steinberg (Brookhaven National Laboratory (US))

steinberg_dis2022_epjformat-4.pdf

Steinberg_DIS2022_v2.pdf

11:00 → 11:30 Coffee break

11:30 → 13:00 Plenary sessions: Plenary 2

Convener: Amanda Sarkar (University of Oxford (GB))

11:30 Parton showers

Speaker: Mrinal Dasgupta (University of Manchester (GB))

md-dis-2022-ps.pdf

12:00 Recent highlihgts on QCD, EW, and Top Physics from the LHC

Speaker: Alexander Josef Grohsjean (Deutsches Elektronen-Synchrotron (DE))

agrohsje_smqcdtop_dis2022.pdf

12:30 EW/Higgs physics and the SMEFT at the LHC

Speaker: Jorge de Blas (Universidad de Granada (ES))

EWHiggs_SMEFT_deBlas.pdf

13:00 → 15:00 Lunch break

15:00 → 16:30 Plenary sessions: Plenary 3

Convener: Elisabetta Gallo (DESY)

15:00 MC Generators today and tomorrow

Speaker: Ilkka Helenius (University of Jyväskylä)

DIS2022_MCEG_Helenius.pdf

15:30 New winds in heavy-ion physics

Speaker: Liliana Apolinario (LIP (PT))

HI-LApolinario.pdf

16:00 Precision QCD for colliders

Speaker: Juan Rojo (VU Amsterdam and Nikhef)

rojo-QCDcolliders-DIS2022.pdf

16:30 → 17:00 Coffee break

17:00 → 18:30 Plenary sessions: Plenary 4

Convener: Abhay Deshpande

17:00 The power of lattice QCD

Speaker: Phiala Shanahan

Shanahan_DIS.pdf

17:30 Spin and 3D nucleon structure

Speaker: Sanghwa Park (University of Mississipi)

DIS2022_spin_SPark.pdf

18:00 Low energy hadronic structure and hadronisation

Speaker: Miguel Arratia (University of California at Riverside)

DIS_Arratia.pdf

Tuesday 3 May

09:00 → 18:50 WG3: Electroweak Physics and Beyond the Standard Model: Session 1

Conveners: Adam Orion Martin (University of Notre Dame (US)), Heather Gray (UC Berkeley/LBNL), Heidi Angelika Rzehak

09:20 Latest results of Higgs Couplings and combination analyses with the ATLAS experiment

With the full Run 2 pp collision dataset collected at 13 TeV, very detailed measurements of Higgs boson properties and its interactions can be performed using its decays into bosons and fermions, shining light over the electroweak symmetry breaking mechanism. This talk presents the latest measurements of the Higgs boson couplings by the ATLAS experiment in various decay channels, including production mode cross sections, simplified template cross sections, as well as their combination and interpretations. Specific scenarios of physics beyond the Standard Model are tested, as well as a generic extension in the framework of the Standard Model Effective Field Theory.

Speaker: Philipp Windischhofer (University of Oxford (GB))

windischhofer_dis.pdf

09:40 Higgs differential cross-sections and CP Higgs couplings results with the ATLAS experiment

With the pp collision dataset collected at 13 TeV, detailed measurements of Higgs boson properties can be performed. The Higgs kinematics and CP properties can be measured with various production and decay modes and interpreted to constrain beyond-the-Standard-Model phenomena. This talk presents the measurements of Higgs boson differential and fiducial cross-sections as well as their combination and interpretations, and limits on the mixing of CP-even and CP-odd Higgs states are set by exploiting the properties of diverse final states.

Speaker: Sagar Addepalli (Brandeis University (US))

DIS2022_SagarAddepalli_final.pdf

10:00 Electroweak corrections to gg -> H and H -> gamma gamma in the singlet extended Standard Model

One of the simplest extensions of the Standard Model (SM) Higgs sector is the Higgs singlet extension in which one adds a singlet to the particle content of the SM. Such models are being studied at the LHC. In the simplest realization of this model, in which the singlet is real, there are two Higgs bosons and only three new parameters, two mixing angles and the mass of the additional Higgs boson. For both Higgs bosons we present results of the NLO (two-loop) electroweak corrections to the main production mechanism through gluon fusion as well as to their decay into two photons for different values of the three parameters. In all cases we discuss the importance of the electroweak corrections.

Speaker: Benjamin Summ (JMU Wuerzburg)

DIS2022_Benjamin_Summ.pdf

10:20 Probing the nature of electroweak symmetry breaking with Higgs boson pair-production at ATLAS

In the Standard Model, the ground state of the Higgs field is not found at zero but instead corresponds to one of the degenerate solutions minimising the Higgs potential. In turn, this spontaneous electroweak symmetry breaking provides a mechanism for the mass generation of nearly all fundamental particles. The Standard Model makes a definite prediction for the Higgs boson self-coupling and thereby the shape of the Higgs potential. Experimentally, both can be probed through the production of Higgs boson pairs (HH), a rare process that presently receives a lot of attention at the LHC. In this talk, the latest HH searches by the ATLAS experiment are reported, with emphasis on the results obtained with the full LHC Run 2 dataset at 13 TeV. In the case of non-resonant HH searches, results are interpreted both in terms of sensitivity to the Standard Model and as limits on the Higgs boson self-coupling. Extrapolations of recent HH results towards the High Luminosity LHC upgrade are also discussed. Search results on new resonances decaying into pairs of Higgs bosons are also reported.

Speaker: Jana Schaarschmidt (University of Washington (US))

dihiggs_atlas.pdf

10:40 Search for rare and exotic decays of the Higgs boson and additional scalar particles in ATLAS

The discovery of the Higgs boson with the mass of 125 GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable to solely explain some observations. Many extensions of the Standard Model addressing such shortcomings introduce additional Higgs-like bosons which can be either neutral or charged. Exotic decays of the Higgs boson also provide a unique window for the discovery of new physics, as the Higgs boson may couple to hidden-sector states that do not interact under Standard Model gauge transformations. Models predicting exotic Higgs boson decays to pseudo-scalars can also explain the g-2 and flavour-sector anomalies, and the galactic centre gamma-ray excess if the additional pseudo-scalar acts as the dark matter mediator. This talk presents recent searches for additional low- and high-mass Higgs bosons, as well as decays of the 125 GeV Higgs boson to new particles, using LHC collision data at 13 TeV collected by the ATLAS experiment in Run 2.

Speaker: Diallo Boye (Brookhaven National Laboratory)

DIS2022Slide.pdf

11:00 Coffee break

11:30 Dark matter searches at LHCb

The LHCb detector at the LHC offers unique coverage of forward rapidities. The detector also has a flexible trigger that enables low-mass states to be recorded with high efficiency, and a precision vertex detector that enables excellent separation of primary interactions from secondary decays. This allows LHCb to make significant (and world-leading) contributions in these regions of phase space in the search for long-lived particles that would be predicted by dark sectors which accommodate dark matter candidates. A selection of results from searches of dark photons, hidden-sector particles, and dark matter candidates produced from heavy-flavour decays among others will be presented, alongside the potential for future measurements in these final states.

Speaker: Carlos Vazquez Sierra (CERN)

DIS_CVS.pdf

11:50 Searches for dark matter with the ATLAS detector

The presence of a non-baryonic Dark Matter (DM) component in the Universe is inferred from the observation of its gravitational interaction. If Dark Matter interacts weakly with the Standard Model (SM) it could be produced at the LHC. The ATLAS experiment has developed a broad search program for DM candidates, including resonance searches for the mediator which would couple DM to the SM, searches with large missing transverse momentum produced in association with other particles (light and heavy quarks, photons, Z and H bosons) called mono-X searches and searches where the Higgs boson provides a portal to Dark Matter, leading to invisible Higgs decays. The results of recent searches on 13 TeV pp data, their interplay and interpretation will be presented.

Speaker: Danika MacDonell (University of Victoria (CA))

DMacDonell_ATLAS_DM_DIS2022.pdf

12:10 Searches for BSM physics using challenging and long-lived signatures with the ATLAS detector

Various theories beyond the Standard Model predict new, long-lived particles with unique signatures which are difficult to reconstruct and for which estimating the background rates is also a challenge. Signatures from displaced and/or delayed decays anywhere from the inner detector to the muon spectrometer, as well as those of new particles with fractional or multiple values of the charge of the electron or high mass stable charged particles are all examples of experimentally demanding signatures. The talk will focus on the most recent results using 13 TeV pp collision data collected by the ATLAS detector.

Speaker: Otilia Anamaria Ducu (IFIN-HH (Bucharest, RO))

BSM_DUCU.pdf

12:30 The dark side of the proton

We study the impact of the inclusion of a light baryonic boson B (which we henceforth refer to as a dark photon), primarily coupled to quarks, as a constituent of the proton; this is achieved by including a dark photon parton distribution function (PDF) in the standard PDF evolution equations. Depending on the proposed mass and coupling of the dark photon, the evolution of light quark and gluon PDFs is distorted to varying degrees. By applying the resulting modified quark and gluon PDFs to high-luminosity high-mass Drell-Yan data, we derive competitive bounds on the mass and coupling of the dark photon.

Speaker: James Moore

darkphoton_dis.pdf

13:10 Lunch

15:00 Measurement of TeV neutrinos with FASERnu at the LHC

FASER$\nu$ is designed to directly detect collider neutrinos of all three flavors for the first time and provide new measurements of their cross-sections at energies higher than those detected from any previous artificial sources. In the pilot run data during LHC Run 2 in 2018, we observed the first neutrino interaction candidates at the LHC, opening a new avenue for studying neutrinos from current and future high-energy colliders. In 2022-2025, during LHC Run 3, we expect to collect $\sim$10,000 flavor-tagged charged-current neutrino interactions in FASER$\nu$, along with neutral-current interactions. Here we present the physics potentials and status of FASER$\nu$.

Speaker: Osamu Sato

FASERnu_DIS2022_Sato.v3.pdf

15:20 Latest results on rare decays at the NA62 experiment at CERN

The NA62 experiment at CERN took data in 2016-2018 with the main goal of measuring the K+ -> pi+ nu nubar decay.
A large sample of charged kaon decays into final states with multiple charged particles has been collected in 2016-2018 by the NA62 experiment at CERN. This sample provides sensitivities to lepton flavour/number violating decays of the charged kaon and of the neutral pion with branching ratios as low as 10-11. Searches for lepton flavour/number violating decays of the charged kaon and the neutral pion to final states containing a lepton pair are presented, improving over the best limits measured so far. The first limit on the K+ → π−π0e+e+ decay rate will also be presented.
Searches for K+→e+N, K+→μ +N and K+→μ+νX decays, where N and X are massive invisible particles, are also performed by NA62 using the whole data set.
An improved upper limit of 1.0 x 10−6 is established at 90% CL on the K+→μ+ννv branching fraction.

Speaker: Artur Shaikhiev (University of Birmingham)

shaikhiev_DIS22.pdf

15:40 Precision measurements with the NA62 experiment at CERN

The NA62 experiment at CERN took data in 2016--2018 with the main goal of measuring the K+ -> pi+ nu nubar decay. The high-intensity fixed-target setup and the detector performance make the NA62 experiment particularly suited to investigate the Standard Model structure and its possible extensions with precision measurements of charged kaon decays.
Results from studies of the radiative kaon decays K+ → pi0e+vg (Ke3g) are reported, using a data sample of O(100k) Ke3g candidates with sub-percent background contaminations recorded in 2017-2018. Preliminary results with the most precise measurements of the Ke3g branching ratios and of T-asymmetry in the Ke3g decay are presented.
The flavour-changing neutral current decay K+ -> pi+ mu+ mu- is induced at the one-loop level in the Standard Model. Preliminary results from an analysis of the K+ -> pi+ mu+ mu- decay are reported, using a large sample of about 3x10^12 kaon decays into two muons recorded with a downscaled di-muon trigger operating along with the main trigger. The most precise determination of the K+ -> pi+ mu+ mu- form-factor parameters 𝑎+ and 𝑏+ has been made by NA62 using data collected in 2017 and 2018

Speaker: Marco Mirra (Universita e sezione INFN di Napoli (IT))

Mirra_DIS2022.pdf

16:00 Measurement of the rare K+ to pi+ nu nubar decay from the NA62 experiment at CERN

The decay K+→π+ νν ̅, with a very precisely predicted branching ratio of less than 10-10, is among the best processes to reveal indirect effects of new physics.
The NA62 experiment reports the branching ratio measurement BR(K+→π+νν¯) = (10.6+4.0−3.4|stat ± 0.9syst) × 10−11 at 68% CL, based on the observation of 20 signal candidates with an expected background of 7.0 events from the total data sample collected at the CERN SPS during 2016-2018. This provides evidence for the very rare K+→π+νν¯ decay, observed with a significance of 3.4σ. The experiment achieves a single event sensitivity of (0.839±0.054) × 10−11, corresponding to 10.0 events assuming the Standard Model branching ratio of (8.4±1.0) × 10−11. This measurement is also used to set limits on BR(K+→π+X), where X is a scalar or pseudo-scalar particle. Details are given of the analysis of the 2018 data sample, which corresponds to about 80% of the total data sample.

Speaker: Riccardo Fantechi (Universita & INFN Pisa (IT))

Fantechi_pinunu_DIS2022_proceedings.pdf

16:20 First measurement of the K± ➞ π0 π0 µ± ν (K00mu4) decay with the NA48/2 experiment at CERN

Preliminary results of the K± → µ ± π0π0ν (Kmu400) decay first observation and analysis based on the NA48/2 data collected in 2003-2004 are presented. The branching ratio measurement is done on the basis of 2437 selected candidates with about 20% background. In the restricted region of squared dilepton mass above 0.03 GeV^2/c^4, the branching ratio is Br(Kmu400, M2(2l)>0.03 GeV2/c4) = (0.65 ± 0.03) x 10-6. The full phase space result is Br(Kmu400) = (3.4 ± 0.2) x 10-6 depending on the decay model extrapolation. This result agrees with a ChPT-based calculation using experimental form factors input.

Speaker: Riccardo Fantechi (Universita & INFN Pisa (IT))

Fantechi_Kmu4_DIS2022_proceedings.pdf

16:40 Coffee break

17:10 Vector boson scattering in CMS

Vector boson scattering is a key production process to probe the electroweak symmetry breaking of the standard model, since it involves both self-couplings of vector bosons and coupling with the Higgs boson. If the Higgs mechanism is not the sole source of electroweak symmetry breaking, the scattering amplitude deviates from the standard model prediction at high scattering energy. Moreover, deviations may be detectable even if a new physics scale is higher than the reach of direct searches. Latest measurements of production cross sections of vector boson pairs in association with two jets in proton-proton collisions at sqrt(s) = 13 TeV at the LHC are reported using a data set recorded by the CMS detector. Differential fiducial cross sections as functions of several quantities are also measured.

Speaker: Andrea Piccinelli (Universita e INFN, Perugia (IT))

DIS2022_VBS_CMS.pdf

17:30 Multiboson production in CMS

This talk reviews recent measurements of multiboson production using CMS data. Inclusive and differential cross sections are measured using several kinematic observables.

Speaker: Alberto Mecca (Universita e INFN Torino (IT))

DIS2022 - Multiboson production in CMS.pdf

17:50 Measurements of multi-boson production at ATLAS

Measurements of multiboson production at the LHC probe the electroweak gauge structure of the Standard Model for contributions from anomalous couplings. In this talk we present recent ATLAS results on the first observation of three W boson production at the LHC (WWW). If available, we also present the differential cross-section measurement of the Z boson produced in association with two photons (Zyy). The studied processes are sensitive to quartic gauge couplings. Moreover, precise boson and diboson differential cross-section measurements are interpreted in a combined Effective Field Theory analysis, allowing to systematically probe gauge boson self-interactions.

Speaker: Ruchi Gupta (Deutsches Elektronen-Synchrotron (DE))

MultiBoson_Ruchi_DIS2022.pdf

18:10 Recent observation and measurements of vector-boson scattering with ATLAS

The scattering of electroweak bosons tests the gauge structure of the Standard Model and is sensitive to anomalous weak boson self interactions. In this talk, we present recent results on weak-boson scattering from the ATLAS experiment using proton-proton collisions at sqrt(s)=13 TeV. We present the first observation of Z+jets production, in two final states where the Z boson decays leptonically and to two neutrinos. In addition, the prospects of measuring exclusive WW production at the HL-LHC will be discussed.

Speaker: Alain Bellerive (Carleton University (CA))

ABellerive_ATLAS_DIS2022.pdf

18:30 Hadronic W-boson decays in off-shell top-quark pair production and decay

We present a Monte Carlo generator for off-shell top-quark pair production and decay in the semileptonic channel. The generator takes form of an extension to a generator which implements $t\bar{t}$ production in the dileptonic channel in terms of the exact matrix elements for $pp\to \ell^+\nu_{\ell}\, l^-\bar{\nu}_{l}b\bar{b}$ at order $\alpha^4 \alpha_s^2$ plus full NLO QCD corrections. The extension transforms existing dileptonic events into semileptonic ones by means of the matrix elements for $pp\to \ell^{\pm}{\nu} q \bar{q} b\bar{b}(+g)$ in a $W^+W^- b\bar{b}$ double-pole approximation. Spin correlations and off-shell effects in top-decay chains are described in terms of exact matrix elements with massive $b$ quarks. Thus, the contributions from $t\bar t$ and $Wt$ single-top production, plus contributions without top resonances and all relevant quantum interferences between different channels are fully included. Matrix elements are matched to the Pythia8 parton shower using the improved resonance-aware POWHEG method within the POWHEG BOX RES framework. These theoretical improvements are especially important for the interpretation of precision measurements of the top-quark mass, for single-top analyses in the $Wt$ channel, and for $t\bar t$ and $Wt$ backgrounds in the presence of jet vetoes or cuts that enhance off-shell effects.

Speaker: Tomas Jezo (WWU ITP)

TJezo.pdf

09:20 → 18:50 WG1: Structure Functions and Parton Densities: Session 1

Conveners: Barak Schmookler (Stony Brook University), Klaus Rabbertz (KIT - Karlsruhe Institute of Technology (DE)), Thomas Cridge (University College London)

09:20 The NNPDF4.0 global analysis and related studies

In this talk we present the NNPDF4.0 global analysis. As compared to its predecessor, NNPDF3.1, the new NNPDF4.0 fit includes 44 new datasets, mostly from the LHC, benefits from a novel machine learning methodology based on hyperparameter optimisation and stochastic gradient descent, is based on state-of-the-art NNLO QCD calculations, and accounts for NLO electroweak corrections and nuclear uncertainties. We demonstrate the robustness of our results with respect to a number of dataset, theory, and methodological variations. We compare NNPDF4.0 with other recent PDF fits and explore its implications for LHC phenomenology. We also discuss the main capabilities of the open-source NNPDF fitting framework. We also present results of ongoing studies based on NNPDF4.0, in particular an updated determination of the strong coupling constant and of methodological improvements

PD The speaker will be indicated at a later date

Speaker: Roy Stegeman

stegeman_dis2022.pdf

09:40 MSHT20 global analysis - General review

MSHT20 is the latest PDF fit from the MRST/MSTW/MMHT/MSHT collaboration, representing our most accurate and precise determination of the PDFs to date it is designed for the LHC precision era. We present a general review and outline further progress which has been made. This includes the effects of varying the strong coupling α_S (M_Z^2) and the masses of the charm and bottom quarks. We determine the preferred value, and accompanying uncertainties, when we allow α_S (M_Z^2) to be a free parameter in the MSHT20 global analyses of deep-inelastic and related hard scattering data, at both NLO and NNLO in QCD perturbation theory. We also perform fits where we allow the heavy quark masses m_c and m_b to vary away from their default values and examine the PDF sensitivity. We make all resulting PDFs sets available.

Speaker: Lucian Harland-Lang (University of Oxford)

lhl_msht_DIS.pdf

10:00 The CTEQ-TEA global analysis of PDFs

We discuss recent developments in the global QCD analysis of parton distribution functions by CTEQ-TEA collaboration.

Speaker: Prof. Pavel Nadolsky (Southern Methodist University)

m503.pdf

10:20 PDF4LHC21: Benchmarking, Combination and Phenomenology

Motivated by recent progress in the PDF determinations carried out by the CT, MSHT, and NNPDF groups, we present an updated combination of global PDF fits: PDF4LHC21. It is based on the Monte Carlo combination of the CT18, MSHT20, and NNPDF3.1 sets followed by either its Hessian reduction or its replica compression. Extensive benchmark studies are carried out in order to disentangle the origin of the differences between the three global PDF sets. In particular, dedicated fits based on almost identical theory settings and input datasets have been performed by the three groups, highlighting the role played by the respective fitting methodologies. We will compare the new PDF4LHC21 combination with its predecessor, PDF4LHC15, and study the phenomenological implications of PDF4LHC21 for a representative selection of inclusive, fiducial, and differential cross sections at the LHC. The PDF4LHC21 combination will be made available via the LHAPDF interface for the upcoming Run III of the LHC and beyond.

Speaker: Thomas Cridge (University College London)

PDF4LHC21_DIS2022_Cridge.pdf

10:40 Impact of jet-production data on the next-to-next-to-leading-order determination of HERAPDF2.0 parton distributions

The HERAPDF2.0 ensemble of parton distribution functions (PDFs) was introduced in 2015. The final stage is presented, a next-to-next-to-leading-order (NNLO) analysis of the HERA data on inclusive deep inelastic $ep$ scattering together with jet data as published by the H1 and ZEUS collaborations. A perturbative QCD fit, simultaneously of $\alpha_S(M_Z^2)$ and and the PDFs, was performed with the result $\alpha_S(M_Z^2) = 0.1156 \pm 0.0011~{\rm (exp)}~ ^{+0.0001}_{-0.0002}~{\rm (model}$ ${\rm + parameterisation)}~ \pm 0.0029~{\rm (scale)}$. The PDF sets of HERAPDF2.0Jets NNLO were determined with separate fits using two fixed values of $\alpha_S(M_Z^2)$, $\alpha_S(M_Z^2)=0.1155$ and $0.118$, since the latter value was already chosen for the published HERAPDF2.0 NNLO analysis based on HERA inclusive DIS data only. The different sets of PDFs are presented, evaluated and compared. The consistency of the PDFs determined with and without the jet data demonstrates the consistency of HERA inclusive and jet-production cross-section data. The inclusion of the jet data reduced the uncertainty on the gluon PDF. Predictions based on the PDFs of HERAPDF2.0Jets NNLO give an excellent description of the jet-production data used as input.

Speaker: Katarzyna Wichmann (Deutsches Elektronen-Synchrotron (DE))

kwichmann-nnloJets-dis22.pdf

11:00 Coffee break

11:30 Toward precise and robust unpolarized PDFs

Recent progress in global analyses have led to pressing questions about precision and accuracy. NNLO PDFs must balance between the precision of experimental constraints and robustness (stability) with respect to the choice of experimental sets and methodological assumptions. We critically compare various strategies for achieving this balance in the Hessian and Monte Carlo formalisms adopted by CTEQ-TEA and other PDF-fitting groups. In typical applications, the differences among these strategies can be as important as missing higher-order corrections. We investigate this topic on the example of NNLO predictions for key LHC processes based on PDFs by the various groups. We comment on timely statistical concepts and confront those to physical constraints.

Speakers: Aurore Courtoy (Instituto de Física, UNAM), Pavel Nadolsky (Southern Methodist University), Tie-Jiun Hou

AC_WG1_hopscotch_DIS_22b.pdf

11:50 Drell-Yan cross-sections with fiducial cuts - impact of linear power corrections and 𝑞𝑇-resummation in PDF determinations

We present a QCD analysis of Drell-Yan W and Z cross-sections using a wide range of measurements from the RHIC, Tevatron and LHC colliders, together with the Deep Inelastic Scattering data from the HERA-2 collider. The study is performed using the xFitter framework and employs a consistent set of theoretical predictions at NNLO in QCD and NLO in EW couplings. Predictions using modern PDFs are confronted with the data, emphasizing the description and PDF impact of new measurements not yet included in global PDF determinations. A PDF fit to these data is also presented, using a novel prescription reducing the fit sensitivity to missing higher orders and their uncertainties.

Speaker: Alessandro Guida (Deutsches Elektronen-Synchrotron (DE))

DIS22_proceeding_Guida.pdf

DIS-presentation_02-05-22.pdf

12:10 Parton distributions with scale uncertainties: a Monte Carlo sampling approach

We present the MCscales approach for incorporating scale uncertainties in parton
distribution functions. The method builds on the Monte Carlo sampling method
for propagating experimental uncertainties to PDFs that underlies the NNPDF
approach, by extending it to the space of factorisation and renomalisation
scales for the processes entering a PDF fit. A prior probability is assigned to
each scale combinations affecting the PDF replicas in the Monte Carlo ensemble
and a posterior probability is obtained by selecting replicas that satisfy
fit-quality criteria. Our approach allows one to exactly match the scale
variations in the PDFs with those in the partonic cross section, thus
accounting for the full correlations between the two. We illustrate the
opportunities for phenomenological exploration made possible by our
methodology, by studying the correlations between scale variations in PDFs
and those in the partonic cross sections for a variety of LHC observables. Sets
of PDFs enriched with scale information are provided, along with a set of tools
to use them.

Speaker: Z.D. Kassabov-Zaharieva

talk.pdf

12:30 MSHT20 Approximate N3LO Parton Distribution Functions with Theoretical Uncertainties

We present a general formalism for the inclusion of theoretical uncertainties from missing higher orders into a parton distribution function (PDF) fit. We demonstrate how using the currently available knowledge about the next-to-next-to-next-to-leading order (N$^3$LO), an order above the standard NNLO used in current PDF fits, can provide consistent, justifiable and explainable estimates for missing higher order uncertainties (MHOUs). With N$^3$LO approximations we allow for a fully consistent approximate N$^3$LO global fit. Using an expanded Hessian procedure from previous MSHT fits, we present the first approximate N$^3$LO PDF fit with theoretical uncertainties, and analyse the differences between these N$^3$LO PDFs and the standard NNLO PDFs.

Speaker: Jamie McGowan

DIS_MSHTN3LO_talk_2022.pdf

12:50 Theory uncertainties from missing higher orders in PDF fits

Almost all PDF fits so far take into account experimental uncertainties but not the uncertainties on theoretical predictions. Because theoretical predictions are typically computed at finite order in perturbation theory, they suffer from (often sizeable) uncertainties due to the missing higher orders. In a recent NNPDF study, theory uncertainties evaluated using scale variation have been included in a PDF fit for the first time. However, scale variation is not always a reliable tool for estimating the size of missing higher orders. I will consider a new approach for evaluating theory uncertainties that I have recently proposed, built upon the Cacciari-Houdeau model, which is more reliable than scale variation and has the great advantage of having a clear probabilistic meaning.

Speaker: Marco Bonvini (INFN, Rome 1 Unit)

bonvini_DIS2022.pdf

13:10 Lunch

15:00 Constraining the nuclear gluon PDF with heavy quark production data

Gluon nuclear Parton distribution functions (nPDFs) have been the subject of many studies over the past years, since they are important for many processes and difficult to constrain. Recently, nCTEQ15 nPDFs have been updated with vector boson and single inclusive hadron production data to address this issue. To constrain the gluon nPDF further, particularly towards $x$ values smaller than $10^{-4}$, we present a new global analysis that employs a data driven approach to include the vast body of heavy quark production data from the LHC. The approach allows control over the theoretical uncertainties and can potentially be used for a wide range of produced particles.

Speakers: Pit Duwentaester, Khoirul Faiq Muzakka

Duwentäster-Muzakka_slides.pdf

15:20 Proton-PDF uncertainties in nuclear-PDFs fitting with p+Pb W± data

We present a systematical study on proton-PDF uncertainties in the extraction of nuclear PDFs from W$^\pm$ production data in proton-lead collisions, using the theoretical covariance matrix and Hessian PDF reweighting methods to quantify the impact. We then discuss different ways to mitigate these theoretical uncertainties, including self-normalization, forward-to-backward and nuclear modification ratios, and charge asymmetries, indicating the advantages and disadvantages in each of these approaches. Finally, using a simple estimate on the achievable statistics at the LHC Run 3, we argue that propagating the proton-PDF uncertainties into nuclear PDF fits can become increasingly important in the future.

Speaker: Petja Paakkinen

Paakkinen_DIS2022.pdf

15:40 TUJU21: Nuclear PDFs with electroweak-boson data at NNLO

Nuclear parton distribution functions (nPDFs) quantify the initial-state nuclear effects and provide a factorization-based input for perturbative calculations in nuclear collisions. These distributions can be determined in a global QCD analysis using wide range of experimental data. In addition to older fixed-target deep inelastic scattering and Drell-Yan dilepton production data, several analyses from p+Pb collisions at the LHC provide further constraints and extend the kinematic reach of applicable data. Here we present an update of our previous TUJU19 analysis where we now include also electroweak-boson production data recently measured by ATLAS and CMS. For the first time, LHC data are included in a nPDF analysis performed at next-to-next-to-leading (NNLO) order in pertrubative QCD. As before, our setup is based on the open-source analysis framework xFitter and we fit our own proton baseline ensuring fully consistent setup. We find a good agremeent with the applied data and that the resulting $\chi^2/N_{\mathrm{df}}$ is significantly smaller in case of NNLO analysis (0.84) compared to our NLO analysis (0.94). We compare our results to other published nPDF fits and find a reasonable agreement given the large uncertainties especially for the flavour dependence. Also, we present comparisons between our NNLO calculations and electroweak-boson production data in Pb+Pb collisions from ATLAS and CMS.

Speaker: Dr Ilkka Helenius (University of Jyväskylä)

DIS2022_TUJU21_Helenius.pdf

proceedings_DIS2022_TUJU21.pdf

16:00 nNNPDF3.0: Evidence for a modified partonic structure in heavy nuclei

We present an updated determination of nuclear parton distributions (nPDFs) from a global NLO QCD analysis of hard processes in fixed-target lepton-nucleus and proton-nucleus together with collider proton-nucleus experiments. In addition to neutral- and charged-current deep-inelastic and Drell-Yan measurements on nuclear targets, we consider the information provided by the production of electroweak gauge bosons, isolated photons, jet pairs, and charmed mesons in proton-lead collisions at the LHC across centre-of-mass energies of 5.02 TeV (Run I) and 8.16 TeV (Run II). For the first time in a global nPDF analysis, the constraints from these various processes are accounted for both in the nuclear PDFs and in the free-proton PDF baseline. The extensive dataset underlying the nNNPDF3.0 determination, combined with its model-independent parametrisation, reveals strong evidence for nuclear-induced modifications of the partonic structure of heavy nuclei, specifically for the small-x shadowing of gluons and sea quarks, as well as the large-x anti-shadowing of gluons. As a representative phenomenological application, we provide predictions for ultra-high-energy neutrino-nucleon cross-sections, relevant for data interpretation at neutrino observatories. Our results provide key input for ongoing and future experimental programs, from that of heavy-ion collisions in controlled collider environments to the study of high-energy astrophysical processes.

Speaker: Tommaso Giani (Nikhef National institute for subatomic physics (NL))

dis.pdf

16:20 Modification of partonic structure in a bound nucleon and global QCD analyses.

We report the results of a new global QCD analysis which includes deep-inelastic $e/\mu$ scattering (DIS) data off proton and deuterium, as well as lepton pair production in Drell-Yan process in $pp$ and $pD$ collisions and $W^\pm/Z$ boson production data from $pp$ and $p \bar p$ collisions at LHC and Tevatron. We address nuclear corrections in DIS in terms of a nuclear convolution model with bound (off-shell) nucleons, in which the off-shell correction is responsible for modification of parton distributions in bound nucleons [1,2]. The relevant off-shell function is determined in our analysis along with proton PDFs. Results are compared with the ones previously obtained by different studies using DIS data from both the deuterium [3,4] and heavy nuclei [1,2]. A number of systematic studies have been performed aiming to estimate the uncertainties arising from the use of various deuterium data sets, from the model of high twist contributions to the structure functions, from the treatment of target mass corrections, as well as from the nuclear corrections in the deuteron. We provide our predictions for the ratios of structure functions $F_2^D/F_2^p$ and $F_2^n/F_2^p$, and for the $d/u$ ratio of the quark distributions, focusing at the region of high Bjorken $x$, and compare them with the ones obtained by other QCD analyses, as well as with recent data from the MARATHON experiment [5].

References:

[1] S.A. Kulagin and R. Petti, Global study of nuclear structure functions, Nucl. Phys. A 765 (2006) 126-187.
[2] S.A. Kulagin and R. Petti, Nuclear parton distributions and the Drell-Yan process, Phys. Rev. C 90 (2014), 045204.
[3] S.I. Alekhin, S.A. Kulagin and R. Petti, Nuclear Effects in the Deuteron and Constraints on the d/u Ratio, Phys. Rev. D 96 (2017), 054005.
[4] A. Accardi et.al, Constraints on large-x parton distributions from new weak boson production and deep-inelastic scattering data, Phys. Rev. D 93 (2016), 114017.
[5] MARATHON Collaboration, Measurement of the Nucleon F2n/F2p Structure Function Ratio by the Jefferson Lab MARATHON Tritium/Helium-3 Deep Inelastic Scattering Experiment, e-Print: 2104.05850 [hep-ex]

Speaker: Roberto Petti (U. of South Carolina, US)

DIS22-D-Petti.pdf

16:40 Coffee break

17:10 Short-range correlations and the phenomenological determination of nuclear PDFs

We construct a new parametrization of nuclear PDFs (nPDFs) inspired by short-range correlation (SRC) models, and implement this in a global fit. The SRC motivated parametrization decomposes the nPDFs into a free nucleon component, and a part describing the formation of the bound nucleon pairs. Here, the A-dependence enters only through multiplicative factors describing the number of the nuclear SRC pairs. This new parametrization yields a good description of a wide range of data with a quality comparable to the traditional parameterization. Additionally, the fraction of SRC nucleon pairs appears to rise uniformly with the increasing mass of the nuclei (from about 10% to 30%). We also observe that the number of SRC proton and neutrons are comparable across the full range of nuclei, suggesting that the SRC pairs are proton-neutron combinations in general agreement with current SRC models.

Speaker: Aleksander Kusina

kusina_DIS2022.pdf

17:30 Global QCD analysis of pion parton distributions with threshold resummation

We perform the first global QCD analysis of pion valence, sea quark, and gluon distributions within a Bayesian Monte Carlo framework with threshold resummation on Drell-Yan cross sections at next-to-leading logarithmic accuracy. Exploring various treatments of resummation including in Mellin-Fourier and double Mellin space, we find that the behavior of the valence quark distribution at large-$x$ $\sim (1-x)^{\beta_v}$ can differ significantly, with $\beta_v$ ranging from $≈1$ to $> 2.5$ at the input scale.

Speaker: Patrick Barry

Barry_Resummation.pdf

17:50 Estimating missing higher orders in transverse momentum distributions using resummations

Missing higher order uncertainties (MHOU) in perturbative computations are usually estimated by varying the unphysical scales present in the process. However, it is known that scale variation prescriptions often underestimate the actual uncertainty. In this talk, we present a more reliable approach to approximate the unknown next-to-next-to-leading order (NNLO) transverse momentum distribution of colourless final states, namely the Higgs boson produced via gluon fusion and the lepton pair produced via Drell--Yan (DY) mechanism. The approximation we construct relies on the combination of the various resummation formalisms, namely threshold, small-pt and high energy resummations, by exploiting the singularity structure of the large logarithms in Mellin space. We show that for the case of the Higgs boson production, the approximate NNLO transverse momentum distribution amounts to a correction of a few percent with respect to the NLO result with a reduction in the scale dependence.

Speaker: Tanjona R. Rabemananjara (NIKHEF & VU Amsterdam)

dis2022-proceeding.pdf

dis2022-tr.pdf

18:10 Emergence of resummation scales in the evolution of the QCD strong coupling and PDFs

The QCD strong coupling (alpha_s) and the parton distribution functions (PDFs) of the proton are fundamental ingredients for phenomenology at high-energy facilities such as the Large Hadron Collider (LHC).
It is therefore of crucial importance to estimate any theoretical uncertainties associated to them.

Both alpha_s and PDFs obey their own renormalisation-group equations (RGEs) whose solution determines their scale evolution.
Although the kernels that govern these RGEs have been computed to very high perturbative precision, they are not exactly known.

In this contribution, we present a procedure that allows us to assess the uncertainty on the evolution of alpha_s and PDFs due to our imperfect knowledge of their respective evolution kernels.
Inspired by transverse-momentum and threshold resummation, we introduce additional scales, that we dubbed resummation scales, that can be varied to estimate the uncertainty on the evolution of alpha_s and PDFs at any scale.

As a test case, we consider inclusive deep-inelastic-scattering structure functions in a region relevant for the extraction of PDFs.
We study the effect of varying these resummation scales and compare it to the usual renormalisation and factorisation scale variations.

Speaker: Dr Francesco Hautmann (Oxford University, Antwerp University)

tk_DIS22_3may.pdf

wtup_hyst.pdf

18:30 Emergence of pion and proton parton distributions

We will report on recent works featuring the parton distribution functions (DFs) of pion-like systems at experimental scales, following an approach based on the assumption that there is an effective charge which defines an evolution scheme for DFs that is all-orders exact. Within this framework, strict lower and upper bounds on all Mellin moments of the valence-quark DFs are derived. Furthermore, valence, glue and all flavor sea DFs can be derived from contemporary results from numerical simulations of lattice-regularised QCD. The results from the exploited simulations are seen to obey the derived bounds and become plainly consistent with those obtained from Constinuum Schwinger methods, behaving at large values of the light-front momentum fraction as prescribed by QCD. Finally, we will discuss the extension of the same approach to the proton system.

Speakers: José Rodríguez-Quintero, Khépani Raya Montaño

DIS2022-PpRQ.pdf

09:20 → 18:50 WG2: Small-x, Diffraction and Vector Mesons: Session 1

Conveners: Daria Sokhan (CEA Saclay / Glasgow U.), Guillaume Beuf, Rafał Staszewski (IFJ PAN Cracow (PL))

09:20 Pseudo- and quasi-PDFs in the BFKL approximation

To calculate the PDFs from first principles in Lattice gauge theories
it is convenient to consider the Ioffe-time distribution defined through gauge-invariant bi-local operators with spacelike separation.
Lattice calculations provide values for a limited range of the distance separating the bi-local operators. In order to perform the Fourier transform and obtain the pseudo- and the quasi-PDFs, it is then necessary to extrapolate the large-distance behavior.

I will discuss the formalism one may use to study the behavior of the Ioffe-time distribution at large distances and show that the pseudo-PDF and quasi-PDF are very different in this regime. Using light-ray operators, I will also show that the higher twist corrections of the quasi-PDF come in not as inverse powers of $P$ but as inverse powers of $x_B P$.

Speaker: Giovanni Antonio Chirilli

DIS2022-qPDF.pdf

09:40 Structure functions from renormalization group improved small x evolution

We perform the fit to the structure function F2 data from HERA including terms due to the resummation at small x. The equation for the unintegrated gluon density is solved, previously established within the renormalization group improved small x framework. We find very good description of the structure function F2 and its charm component Fc2. The resulting unintegrated gluon density is found to be consistent with the calculations based on similar approaches available in the literature, with only slightly higher intercept value.

Speakers: Anna Stasto (Pennsylvania State University (US)), Anna Stasto, Anna Stasto

anna_stasto_ccss.pdf

10:00 Nonlinear evolution in the next-to-leading order approach vs experimental HERA data.

We present our theoretical results of the next-to-leading order approach (NLO) of [Eur. Phys. J. C 80, 1029 (2020)] in contrast with the experimental HERA data. This approach includes the re-summed NLO corrections to the kernel of the evolution equation, the correct asymptotic behavior in the NLO at $\tau = r^{2}Q_{S}^{2} \gg 1$; the impact parameter dependence of the saturation scale in accord with the Froissart theorem as well as the nonlinear corrections. We successfully describe the experimental data with the quality, than in the leading order fits with larger number of the phenomenological parameters. It is demonstrated, that the data could be described, taking into account both the diffusion on ln($k_T$), which stems from perturbative QCD, and the Gribov’s diffusion in impact parameters. It is shown our first ability to describe the data at rather large values of $\bar{\alpha}_{S}$.

Speaker: Michael Sanhueza

SANHUEZA_DIS2022_NLOBKFit.pdf

10:20 One-loop light cone wave functions with massive quarks

A central ingredient in calculations of scattering processes in the high energy saturation regime of QCD is the light cone wavefunction. It is a universal QCD quantity encoding the light cone gauge partonic structure of a high energy projectile, and a necessary ingredient in cross section calculations for different scattering processes. This talk will report on the recent calculation of the light cone wave functions for a longitudinal [1] or transverse [2] virtual photon to split into quark-antiquark states, including for the first time quark masses at one loop accuracy. These wave functions can be used to calculate cross sections for several precision probes of perturbative gluon saturation at the Electron-Ion Collider. Using these wave functions we derive, for the first time, the total dipole picture DIS cross sections for longitudinal and transverse virtual photons with quark masses. The calculation has required solving a longstanding issue concerning quark mass renormalization in light cone perturbation theory. The quark masses are renormalized in the pole mass scheme, satisfying constraints from the requirement of Lorentz invariance of the quark Dirac and Pauli form factors.

[1] G. Beuf, T. Lappi and R. Paatelainen, Phys.Rev.D 104 (2021) 5, 056032, [2103.14549 [hep-ph]]
[2] G. Beuf, T. Lappi and R. Paatelainen, 2112.03158 [hep-ph]

Speaker: Tuomas Lappi

dis22.pdf

10:40 Evidence for the maximally entangled low x proton in Deep Inelastic Scattering

We investigate the proposal by Kharzeev and Levin of a maximally entangled proton wave function in Deep Inelastic Scattering at low x and the proposed relation between parton number and final state hadron multiplicity. Contrary to the original formulation we determine partonic entropy from the sum of gluon and quark distribution functions at low x, which we obtain from an unintegrated gluon distribution subject to next-to-leading order Balitsky-Fadin-Kuraev-Lipatov evolution. We find for this framework very good agreement with H1 data. We furthermore provide a comparison based on NNPDF parton distribution functions at both next-to-next-to-leading order and next-to-next-to-leading with small x resummation, where the latter provides an acceptable description of data.

Speaker: Krzysztof Marek Kutak (Polish Academy of Sciences (PL))

DISproceedings.pdf

entanglement.pdf

11:00 Coffee break

11:30 Diffractive longitudinal structure function at the Electron Ion Collider

Possibilities for the measurement of the longitudinal structure function in diffraction FDL at the future US Electron Ion Collider are investigated. The sensitivity to FDL arises from the variation of the reduced diffractive cross section with centre-of-mass energy. Simulations are performed with various sets of beam energy combinations and for different assumptions on the precision of the diffractive cross section measurements. Scenarios compatible with current EIC performance expectations lead to an unprecedented precision on FDL at the 5-10 % level in the best measured regions. While scenarios with data at a larger number of centre-of-mass energies allow the extraction of FDL in the widest kinematic domain and with the smallest uncertainties, even the more conservative assumptions lead to precise measurements. The ratio RD of photoabsorption cross sections for longitudinally to transversely polarised photons can also be obtained with high precision using a separate extraction method.

Speaker: Anna Stasto

anna_stasto_fl_diff.pdf

11:50 Probing gluon saturation via diffractive jet production at the EIC

The study of the dense gluonic matter emerging in QCD at high energies represents one of the main goals of the experimental program at the future Electron-Ion Collider. We demonstrate that dijet production via inelastic diffraction is a promising channel for probing gluon saturation, including in the hard regime at high photon virtuality, where the collinear factorisation applies. By inelastic diffraction we mean a process in which the two hard jets -- a quark-antiquark pair generated by the decay of the virtual photon -- are accompanied by a softer gluon jet, emitted by the quark or the antiquark. This process can be described as the elastic scattering between an effective gluon-gluon dipole and the nucleus. The cross section takes a factorised form, between a hard factor and a unintegrated (``Pomeron'') gluon distribution describing the transverse momentum imbalance between the hard dijets. The dominant contribution comes from the black disk limit and leads to a dijet imbalance of the order of the target saturation momentum $Q_s$ evaluated at the rapidity gap. Integrating out the dijet imbalance, we obtain a collinear factorisation where the initial condition for the DGLAP evolution is set by gluon saturation.

Speaker: Edmond Iancu (Université Paris-Saclay (FR))

Iancu_DIS2022.pdf

12:10 Promoting gluon saturation to higher precision with dijets at the EIC

The search for gluon saturation is one of the main pillars for the scientific program of the future Electron-Ion Collider (EIC). In recent years, significant progress has been made in advancing saturation physics to a precision science as we prepare for the EIC era. We contribute to these efforts by performing the first complete next-to-leading order (NLO) computation of inclusive dijet production in deeply inelastic electron-nucleus scattering at small-x within the Color Glass Condensate (CGC).

I will highlight three aspects of our computation: the cancellation of ultra-violet divergences, the JIMWLK factorization of the rapidity logarithms, and the cancellation of infrared and collinear singularities within the small-cone approximation. Furthermore, I will discuss the applicability of our results in the back-to-back regime and the emergence of Sudakov logarithms. I will conclude by outlining further extensions of our work that are relevant for the search of gluon saturation at the EIC.

P. Caucal, FS, R. Venugopalan. Dijet impact factor in DIS at next-to-leading order in the Color Glass Condensate. arXiv:2108.06347 [hep-ph]. JHEP 11 (2021) 222

P. Caucal, FS, B. Schenke, R. Venugopalan. Back-to-back dijet production in DIS at next-to-leading order in the Color Glass Condensate. (In progress)

Speaker: Farid Salazar (UCLA/UCB/LBNL)

DIS_talk_final.pdf

12:30 One loop corrections to inclusive di-hadron production in DIS at small x

Using the spinor helicity formalism we calculate the one-loop corrections to inclusive di-hadron production in DIS at small $x$ using the Color Glass Condensate description of the target proton or nucleus. It is shown that all divergences either cancel or can be absorbed into evolution of hadron fragmentation functions. We discuss phenomenological applications of our results to EIC and ultra-peripheral collisions at LHC.

Speaker: Jamal Jalilian-Marian

proceedings-jjm.pdf

12:50 NLO QCD corrections to inclusive J/psi and Upsilon photoproduction cross sections at lepton-hadron colliders

We revisit inclusive $J/\psi$ and $\Upsilon$ photoproduction at lepton-hadron colliders, namely in the limit when the exchanged photon is quasi real. Our computation includes the next-to-leading-order (NLO) $\alpha_s$ corrections to the leading-order contributions in $v^2$.

We consider first large-$P_T$ inclusive photoproduction of $J/\psi$ at HERA and provide NLO predictions for the EIC (Phys.Lett.B 811 (2020), 135926).

Then we focus on the total inclusive $J/\psi$ and $\Upsilon$ photoproduction cross sections at NLO all the way from AMBER to FCC-eh energies, passing by those of the EIC and LHeC. We investigate where such measurements could be used to improve our knowledge of gluon densities at scales as low as a couple of GeV (e-Print: 2112.05060 [hep-ph]).

Speaker: Maxim Nefedov (NCBJ, Warsaw)

Nefedov_Quarkonium_production_slides.pdf

13:10 Lunch

15:00 Investigating saturation effects in leading neutron spectra with the color dipole model

We investigate the Feynman-$x$ spectra of the neutrons produced in the very forward direction in $ep$ collisions using the impact-parameter dependent color dipole model with and without saturation. Our analysis demonstrates that the W and $Q^2$ dependence of the cross-section are independent of the presence of a forward neutron, as predicted by Feynman-scaling. The models prediction are compared with the available HERA data for leading neutrons in $6

Speaker: Mr Arjun Kumar (Indian Institute of Technology Delhi)

arjun_kumar_dis2022.pdf

15:20 Centrality classification of ultraperipheral PbPb collisions and observation of impact parameter dependence of photon-photon interactions in UPCs with the CMS experiment

New measurements of impact parameter dependence of photon-photon interactions in ultraperipheral PbPb collisions (UPC) are presented, using data collected by the CMS detector during the LHC Run 2. The “UPC centrality” is classified based on the number of neutrons (including 0, 1, or at least two) detected in the very forward pseudorapidity to control the impact parameter of UPCs. The back-to-back azimuthal correlation structure of $\mu^+\mu^-$ pairs from leading-order photon-photon scattering is measured and found to be significantly broader for events with a larger number of emitted neutrons from each nucleus, corresponding to interactions with a smaller impact parameter. This observation provides the first data-driven demonstration that the average transverse momentum of photons emitted from relativistic heavy ions has an impact parameter dependence. These results are compared with quantum electrodynamics calculations and provide crucial new constraints on models of photon-induced interactions in ultraperipheral collisions. Searches for possible final-state effects on lepton pairs caused by traversing a quark-gluon plasma in hadronic PbPb collisions and new physics beyond the standard model are also discussed with the baseline provided by the new results.

Speaker: Irais Bautista Guzman (Autonomous University of Puebla (MX))

DIS_.pdf

15:40 ATLAS measurements of photo-nuclear processes in Pb+Pb collisions

Ultra-peripheral collisions (UPC) of relativistic heavy-ion beams lead to a diverse set of photon-nucleus interactions. This talk presents two recent ATLAS measurements of photo-nuclear processes in Pb+Pb collisions at 5.02 TeV. The first measurement is that of photon-induced dijet production in UPC events. The clean environment of these events allows for precision measurements in a phase-space region where significant nuclear PDF modifications are expected to be present and which are not strongly constrained by previous measurements. The second measurement is that of two-particle azimuthal correlations in photo-nuclear collisions, which are found to show features that are similar to those observed in pp, p+Pb, and Pb+Pb collisions. Fourier coefficients of the correlations are measured as a function of charged-particle multiplicity and transverse momentum and compared to corresponding measurements in pp and p+Pb collisions and to quantitative theoretical calculations. The correlation measurements can shed light on the QCD dynamics of the novel, extremely asymmetric colliding systems. Understanding the hadronic fluctuation spectrum of the photon in this fashion is also critical for maximizing the precision of measurements at the future Electron-Ion Collider.

Speaker: Benjamin Jacob Gilbert (Columbia University (US))

Gilbert_DIS_Photonuclear_ATLAS.pdf

16:00 Probing Gluon Bose Correlations in Deep Inelastic Scattering

We study correlations originating from the quantum nature of gluons in a hadronic wave function. Bose-Einstein correlation between identical particles lead to the enhancement in the number of pairs of gluons with the same quantum numbers and small relative momentum. We show that these preexisting correlations can be probed in Deep Inelastic Scattering experiments at high energy. Specifically, we consider diffractive trijet production. The azimuthal dependence displays a peak at the zero relative angle between the transverse momentum imbalance of the photon-going dijet and the transverse momentum of the hadron-going jet. Our calculations explicitly show that the peak originates from Bose enhancement. Comparing electron-proton to electron-nucleus collisions, we demonstrate that the nuclear target enhances the relative strength of the peak. With the future high luminosity Electron-Ion Collider the proposed measurements of gluon Bose enhancement may become experimentally feasible

Speaker: Ming Li

Trijet_talk_by_MingLi_DIS2022.pdf

16:20 Exclusive photoproduction of heavy quarkonia pairs in ep collisions

We present our theoretical results for the exclusive photoproduction of heavy quarkonia pairs in the kinematics of the future high-energy colliders, like the future Electron Ion Collider (EIC), the Large Hadron electron Collider (LHeC), and the Future Circular Collider (FCC-he). We found that in the leading order over the strong coupling $\alpha_s$ the produced quarkonia have opposite $C$-parity, and predominantly are produced with oppositely directed transverse momenta. Using the Color Glass Condensate (CGC/Sat) approach, we estimated numerically the cross-section of this process for the case of $J/\psi-\eta_c$ pair production in the kinematics of the future accelerators. Finally, we also discuss briefly subleading mechanisms which contribute to production of quarkonia pairs with the same $C$-parity.

Speaker: Marat Siddikov

Proceeding_DIS2022_MSiddikov.pdf

Talk_DIS2022_Marat_Siddikov.pdf

16:40 Coffee break

17:10 DIS dijet production beyond eikonal accuracy

We derive subeikonal corrections to the quark propagator assuming that the quark is propagating through the whole medium in order to study DIS dijet production. We take into account NEik (Next-to-Eikonal) corrections from previous results for splitting before the medium and we calculate a new contribution coming from splitting inside the medium at NEik. This time we include not only corrections that contribute to Next-to-Eikonal accuracy that are due to considering a finite longitudinal width target and the interaction of the quark with the transverse component of the background field, here we also include the dynamics of the target. We then apply these corrections to the DIS dijet cross section for both inclusive and diffractive production.

Speaker: Arantxa Tymowska

DIS2022.pdf

17:30 Boer-Mulders Function at Small-x

We apply the formalism developed earlier by Kovchegov, Pitonyak, and Sievert for constructing transverse momentum dependent parton distribution functions (TMDs) at small Bjorken-x to derive the small-x evolution equations for the Boer-Mulders TMD. We construct evolution equations which resum double logarithms $\alpha_s \textrm{ln}^2 (1/x)$, obtaining a closed set of equations in the large $N_c$ limit.

Speaker: M. Gabriel Santiago (The Ohio State University)

DIS_2022_Santiago.pdf

17:50 Partial twist expansion for DIS and DVCS at small x

We propose a novel approach to high energy scattering that allows to interpolate between the Bjorken limit and the Regge limit of QCD. It consists in performing a partial twist expansion of cross-sections which allows to resum to all orders higher twists that contribute to gluon saturation at small x. We discuss the case of gluon mediated DIS and DVCS as a first application. In this framework a novel x-dependent gluon distribution is derived whose quantum evolution generalizes BK/BFKL equations to moderate values of x.

Speakers: Renaud Boussarie (Brookhaven National Lab), Yacine Mehtar-Tani

18:10 Twist decomposition of non-linear effects in the Balitsky-Kovchegov evolution

We investigate the impact of the Balitsky-Kovchegov (BK) non-linear corrections on the initial conditions and evolution of twist components of the DIS cross-section at small x. The twist decomposition of the BK-driven DIS cross-section is performed in the Mellin space. Three main contributions are found that may be interpreted in the OPE framework as: 1) a modification of the input for DGLAP evolution of the leading twist with respect to that from a linear small x evolution, 2) emergence of higher twist contributions driven by the BK nonlinearity, and 3) a non-linear correction to the DGLAP evolution. We perform numerical evaluation of these effects at the leading twist and higher twists in the proton, and find that the dominant BK effects appear at the leading twist. The results have implications for estimates of higher twist corrections in structure functions of the proton and of nuclei at small x.

Speaker: Leszek Motyka

motyka_dis22.pdf

18:30 The parton distributions at small momentum fractions

When parton momentum faction $x$ of hadron becomes small, an enhancement from small-$x$ logarithms shows up, and eventually, we enter into a partonic saturation region. A consistent treatment of the small-$x$ logarithms requires an all-order resummation which can be achieved with the BFKL formalism. However, a boundary to delineate the small-$x$ resummation region from saturation one is ambiguous. In this study, we take a $x$-dependent DIS scale motivated by the saturation model in a global analysis, which improves the QCD description of the HERA DIS data. In parallel, we also explore the BFKL improved DGLAP evolution, which achieves a similar $\chi^2$ for the same data set. We compare various impacts of these two methods on the parton distributions, and also phenomenological implications, including Drell-Yan or Higgs boson production at future hadron colliders (FCC), the ultra-high-energy neutrino-nucleus scattering, and structure function measurements at future electron-hadron colliders (LHeC/FCC-eh).

Speaker: Keping Xie (University of Pittsburgh)

DIS_smallX.pdf

09:20 → 11:30 WG4: QCD with Heavy Flavours and Hadronic Final States: Jet Session 1: inclusive jets and substructure

Conveners: Maria Vittoria Garzelli, Olga Evdokimov (University of Illinois at Chicago (US)), Xuan Li (Los Alamos National Laboratory)

09:20 Multi-differential Jet Substructure Measurement in High Q² Deep-Inelastic Scattering with the H1 Detector

A study of different jet observables in high $Q^{2}$ Deep-Inelastic Scattering events close to the Born kinematics is presented. Differential and multi-differential cross-sections are presented as a function of the jet’s charged constituent multiplicity, momentum dispersion, jet charge, as well as three values of jet angularities. Results are split into multiple $Q^{2}$ intervals, probing the evolution of jet observables with energy scale. These measurements probe the description of parton showers and provide insight into non-perturbative QCD. Unfolded results are derived without binning using the machine learning-based method Omnifold. All observables are unfolded simultaneously by using reconstructed
particles inside jets as inputs to a graph neural network.  Results are compared with a variety of predictions.

H1prelim-22-034

Speaker: Vinicius Massami Mikuni (Lawrence Berkeley National Lab. (US))

DIS_2022_v1.pdf

Multi-differential Jet Substructure Measurement in High Q2 DIS Events with HERA-II Data

09:40 Measurements of jet substructure using the CMS detector

The internal structure of jets allows us to bridge our description and understanding of short-distance physics and color confinement. In this talk, we discuss recent measurements of jet substructure performed using data collected by the CMS experiment at a center-of-mass energy of √s=13 TeV. Measurements of various jet substructure observables, with and without jet grooming, are presented. The measurements are corrected for detector effects and are compared to predictions based on state-of-the-art analytical calculations and Monte Carlo event generators.

Speaker: Cristian Baldenegro Barrera (Centre National de la Recherche Scientifique (FR))

DIS2022_jetsubstructure.pdf

10:00 NNLO QCD corrections in full colour for jet observables at the LHC

Calculations for processes involving a high multiplicity of coloured particles often employ a leading colour approximation, where only the leading colour levels in the expansion of the number of colours Nc are calculated and subleading colour levels, which are suppressed by powers of 1/N^2_c relative to the leading colour, are omitted. This approximation of the full colour result is motivated by the simple 1/N^2_c suppression and the increasing complexity of including subleading colour contributions to the calculation. In this work, we present the calculations using the antenna subtraction method in the NNLOJET framework for the NNLO QCD corrections at full colour for several jet observables at the LHC. The single jet inclusive cross section is calculated doubly differential in pT and absolute rapidity and compared with the CMS measurement at 13 TeV. A calculation for dijet production doubly differential in dijet mass and rapidity difference is also performed and compared with the ATLAS 7 TeV data. Lastly, a triply differential dijet cross section in average transverse momentum, rapidity separation and dijet system boost is calculated and compared with the CMS 8 TeV data. The impact of the subleading colour contributions to the leading colour approximation is assessed in detail.

Speaker: Jonathan Mo (University of Zurich)

JMo_FCjets_DIS2022.pdf

10:20 Azimuthal correlations of high transverse momentum jets at next-to-leading order in the parton branching method

We present our recent results published in 10.1140/epjc/s10052-022-09997-1. The azimuthal correlation of high transverse momentum jets in pp collisions is studied by applying PB-TMD distributions to NLO calculations via MCatNLO together with the PB-TMD parton shower. A very good description of the cross section as a function of the di-jet azimuthal separation is observed. In the back-to-back region of a very good agreement is observed with the PB-TMD Set 2 distributions while significant deviations are obtained with the PB-TMD Set 1 distributions. Set 1 uses the evolution scale while Set 2 uses transverse momentum as an argument in αs, and the above observation therefore confirms the importance of an appropriate soft-gluon coupling in angular ordered parton evolution. The total uncertainties of the predictions are dominated by the scale uncertainties of the matrix element, while the uncertainties coming from the PB-TMDs and the corresponding PB-TMD shower are very small. The measurements are also compared with predictions using MCatNLO together with PYTHIA8, illustrating the importance of details of the parton shower evolution.

Speaker: Armando Bermudez Martinez (CMS-DESY)

DIS2022.pdf

DIS_2022_proceedings.pdf

10:40 Studies of multi-jet merging with Parton Branching TMD evolution

Recently a multi-jet merging method has been proposed which incorporates the evolution of TMD distributions [arXiv:2107.01224 [hep-ph]]. We present new studies of differential jet rates in this framework, and results for Drell-Yan (DY) production and multijets. We discuss the reduction of merging scale uncertainties owing to the TMD merging compared to collinear merging, and investigate the dependence of theoretical predictions on the merging scale as a function of DY mass, including the case of high-mass DY at the LHC.

Speaker: Mees van Kampen

Proceedings_AMvanKampen_TMDmerging.pdf

TMD_multi-jet-merging_PB_MeesvanKampen.pdf

11:00 Coffee-break

09:20 → 19:10 WG5: Spin and 3D Structure: Session 1

Conveners: Qinghua Xu (Shandong University), Yoshiyuki Miyachi (Yamagata University (JP)), yoshitaka hatta (BNL)

09:20 Unpolarised Semi-Inclusive DIS at COMPASS

In semi-inclusive deep inelastic scattering (SIDIS) the non-zero transverse momentum of partons is reflected in the transverse momentum $P_T$ of the produced hadrons and in their azimuthal distribution. Assuming Gaussian dependence of transverse momentum dependent (TMD) PDFs and fragmentation functions (FFs) upon quark transverse momentum, exponential distribution of $P_T^2$ is expected. For an unpolarised nucleon, three azimuthal modulations that can be related to combinations of twist-two or higher-twist TMD PDFs and FFs arise: the so-called Cahn effect reflected in a $\cos\phi$ modulation, the $\cos2\phi$ term related to the Boer−Mulders PDF and $\sin\phi$ effect known as beam-spin asymmetry.
In 2016 and 2017, the COMPASS experiment at CERN collected a large sample of SIDIS events using a longitudinally polarised 160 GeV/$c$ muon beam scattering on a liquid hydrogen target. The $P_T^2$ distributions and the amplitudes of the aforementioned azimuthal modulations have been extracted for charged hadrons from part of the data. The $P_T^2$ distributions can be described by two exponentials. The results qualitatively agree with earlier COMPASS measurements with an isoscalar target.

Speaker: Jan Matousek (Charles University (Prague, CZ))

Matousek_20220503.pdf

09:40 Global extraction of unpolarized quark TMDs at N3LL

In this talk we present the most recent extraction of unpolarized transverse-momentum-dependent (TMD) parton distribution functions (PDFs) and TMD fragmentation functions (FFs) from global data sets of Semi-Inclusive Deep-Inelastic Scattering (SIDIS), Drell-Yan and Z boson production. The fit is performed at the (next-to)$^3$ leading logarithmic accuracy in the resummation of qT-logarithms and features flexible non-perturbative functions, which allow to reach a very good agreement with the experimental data. In particular, we address the tension between the low-energy SIDIS data and the theory predictions, and explore the impact of the precise LHC data on the fit results.

Speaker: Matteo Cerutti (Università di Pavia)

Cerutti_DIS2022.pdf

DIS22proceedings_2.pdf

10:00 Simultaneous extraction of collinear and transverse momentum dependent parton densities using high energy Drell-Yan data

Large energy Drell-Yan and $Z$-boson production data have been used to extract transverse momentum dependent parton distribution functions (TMDPDFs). Evolution of TMDPDFs is conveniently described in $b_T$ space, the Fourier conjugate to transverse momentum. The cross section depends on perturbative QCD calculations and non-perturbative TMD functions at low and high regions of the $b_T$ spectrum, respectively. The perturbative QCD description includes the operator product expansion, which has dependence on collinear PDFs. Here, we perform a Monte Carlo global QCD analysis to extract both PDFs and TMDPDFs simultaneously. We explore various TMD factorization methods from the Collins-Soper-Sterman (CSS), Qiu-Zhang (QZ), and zeta prescriptions.

Speaker: Patrick Barry

Barry_TMDs.pdf

10:20 Thrust resummation and rapidity divergencies

Extending TMD factorization to thrust-dependent observables entails difficulties ultimately associated with the behavior of soft radiation. As a consequence, the definition of the TMDs has to be revised, while keeping (and extending) its universality properties. Moreover, the regularization of the rapidity divergences intertwines with the thrust dependence, leading to a new kind of factorization theorem, with unexpected features. In this talk, I will show how to properly factorize the thrust distribution of e+e- annihilation into a single hadron, whose transverse momentum is measured with respect to the thrust axis. The cross section is presented at NLL-accuracy both in thrust and in transverse momentum.

Speaker: Andrea Simonelli (University of Torino and INFN Torino)

simonelli.pdf

10:40 Machine learning-assisted measurement of multi-differential lepton-jet correlations in deep-inelastic scattering with the H1 detector

The lepton-jet momentum imbalance in deep inelastic scattering events offers a useful set of observables for unifying collinear and transverse-momentum-dependent frameworks for describing high energy Quantum Chromodynamics interactions. A recent first measurement was made [1] of this imbalance in the laboratory frame using positron-proton collision data recordedf with the H1 experiment at HERA in the years 2006-2007. Using a new machine learning method, the measurement was performed simultaneously and unbinned in eight dimensions. The first results were presented as as set of four one-dimensional projections onto key observables. This work extends over those results by making use of the multi-differential nature of the unfolded result. In particular, distributions of lepton-jet correlation observables are studied as a function of the kinematic properties of the scattering process, i.e. as a function of the momentum transfer $Q^2>150$ GeV$^2$ and the inelasticity $0.2< y< 0.7$.

H1prelim-22-031
[1] arxiv:2108.12376, submitted to PRL

Speaker: Miguel Arratia (University of California at Riverside)

Arratia_DISWG6.pdf

11:00 Coffee break

11:30 Measurement of target transverse-spin-dependent azimuthal asymmetries in SIDIS at COMPASS

COMPASS is a fixed target high energy physics experiment located at the M2 beamline (SPS, North Area) at CERN. The experiment is collecting data since 2002 covering a broad range of physics topics. Experimental results obtained by COMPASS for spin (in)dependent azimuthal azimuthal effects in semi-inclusive deep inelastic scattering (SIDIS) measurements, play an important role in the general understanding of the three-dimensional nature of the nucleon. Giving access to the entire “twist-2” set of transverse momentum dependent (TMD) parton distribution functions (PDFs) and fragmentation functions (FFs), COMPASS data triggers constant theoretical interest and are being widely used in phenomenological analyses and global data fits.
In 2022 COMPASS is going to accomplish the series of measurements performed between 2002 and 2011 using 190 GeV/c muon beam and longitudinally and transversely polarized deuteron and proton targets, by collecting largest ever sample of SIDIS events with transversely polarized deuteron. This last round of measurements is particularly important for constraining the d-quark transversity and other TMD PDFs
In this talk COMPASS SIDIS results on azimuthal asymmetries, obtained from transversely polarized deuteron and proton data, will be reviewed along with relevant phenomenological and studies global fits. The details on COMPASS 2022 data-taking will be presented.

Speaker: Dr Bakur Parsamyan (CERN, JINR and Turin section of INFN)

Parsamyan_DIS2022_SIDIS.pdf

11:50 Collins and Sivers asymmetries in inclusive ρ0 production from COMPASS

The study of the partonic and spin structure of the nucleon, using semi-inclusive measurements of hadron muoproduction in Deep Inelastic Scattering (DIS), is one of the main objectives of the COMPASS experiment at CERN. Within the QCD parton model approach, the nucleon structure in DIS can be parametrized in terms of Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs), while the hadronization mechanisms are described by the so-called Fragmentation Functions (FFs). Specific convolutions of the TMD PDFs and FFs can be accessed through the measurement of various spin-dependent azimuthal asymmetries in hadron or dihadron productions in DIS. The production of vector mesons in SIDIS is potentially interesting to study the polarized fragmentation and related phenomena. However, this domain is largely unexplored.
In this talk preliminary COMPASS results for the first ever measurement of Collins and Sivers asymmetries in inclusive $\rho^0$ production will be shown. The analysis is based on the SIDIS data-set collected by COMPASS in 2010 using a 160 GeV/c longitudinally polarized $\mu^+$ beam impinging on a transversely polarized $NH_3$ target.
The asymmetries were extracted as function of different kinematic variables and confronted with model expectations.

Speaker: Bakur Parsamyan (CERN, JINR and Turin section of INFN)

Parsamyan_DIS2022_rho0.pdf

12:10 Single spin asymmetry at two loops in SIDIS

In [1] it was shown that gT(x) can contribute to a Single Spin Asymmetry in SIDIS. This contribution
arises through certain two-loop diagrams which provide the necessary imaginary phase for the asymmetry. In this
talk, I discuss our work in [2] where we presented numerical estimates of the above asymmetry at the planned Electron-Ion
Collider. Therein we also included an analogous gluon-initiated contribution arising from the G3T(x) distribution.
In our framework, both gT(x) and G3T(x) were considered in the Wilczek-Wandzura (WW) approximation, i.e., as integrals
of the quark and gluon helicity distributions respectively. Hence these contributions to the asymmetry can be
evaluated unambiguously without inputs from unknown parameters such as genuine twist-3 distributions. We find that
the asymmetry associated with the sin(phi_h - phi_S), sin(phi_S) and sin(2phi_h-phi_S) harmonics can reach up to 1-2%
at the Electron-Ion Collider.

[1] S. Benić, Y. Hatta, H-n. Li, D.-J. Yang, Phys. Rev. D 100 (2019) 9, 094027
[2] S. Benić, Y. Hatta, A. K, H-n. Li, Phys. Rev. D 104 (2021), 094027

Speaker: ABHIRAM KAUSHIK

DIS22.pdf

12:30 Transverse Single-Spin Asymmetry of Midrapidity Heavy Flavor Electrons in 200 GeV $p^{\uparrow}+p$ Collisions at PHENIX

Understanding the transverse spin and momentum structure of the proton is of great interest to the nuclear physics community and it is one of the main goals of the spin physics program at the Relativistic Heavy Ion Collider (RHIC). Transverse single-spin asymmetry measurements for particles produced in proton-proton collisions provide insight into initial and final state spin-momentum and spin-spin parton-hadron correlations. In particular, electrons from heavy flavor decays provide access to initial state spin-momentum correlations of gluons in polarized protons, and allow for constraints to be placed on the antisymmetric and symmetric twist-3 trigluon correlation functions. Electrons are measured at midrapidity at PHENIX using the central arm spectrometers which consist of an electromagnetic calorimeter, a ring-imaging Cherenkov detector, as well as drift and pad chambers. In addition, the silicon vertex detector is used in order to veto background from conversion electrons and increase signal purity. Recent results from the 2015 running period (200 GeV $p^{\uparrow}+p$) will be presented.

Speaker: Dillon Scott Fitzgerald (University of Michigan (US))

FitzgeraldDIS2022_final.pdf

12:50 Transverse Spin Dependent Azimuthal Correlations of Charged Pion Pairs in $p^{\uparrow}p$ collisions at $\sqrt{s} = 200$ and $\sqrt{s} = 510$ GeV at STAR

The transversity distribution, $h^q_1(x)$, describes transversely polarized quarks inside a transversely polarized nucleon. As $h^q_1(x)$ is chiral-odd, it can only be accessed via a process where it couples to another chiral-odd function, such as the spin-dependent interference fragmentation function (IFF), in $p^\uparrow p$ collisions. The coupling of $h^q_1(x)$ and IFF yields an experimentally measurable di-hadron correlation asymmetry, $A_{UT}$. To access $h^q_1(x)$ at high $Q^2$, where the QCD calculation is well understood, precise measurement of $A_{UT}$ at high center-of-mass energies, $\sqrt s$, is crucial. Previously, the STAR experiment at RHIC has measured non-zero $A_{UT}$ using $p^\uparrow p$ data at $\sqrt s= 200$ GeV recorded in 2006 with an integrated luminosity of $1.6$ pb$^{-1}$ and $\sqrt s= 500$ GeV recorded in 2011 with an integrated luminosity of $25$ pb$^{-1}$. In 2015 and 2017, STAR collected additional $\sim 52$ pb$^{-1}$ of $p^\uparrow p$ data at $\sqrt s=200$ GeV and $\sim 350$ pb$^{-1}$ of $p^\uparrow p$ data at $\sqrt s=510$ GeV, which will significantly improve the statistical precision of $A_{UT}$ measurement and thus further constrain global fits of $h^q_1(x)$, especially for $0.07

Speaker: Navagyan Ghimire (STAR Collaboration)

DIS_2022_Slides_V8_final.pdf

13:10 Lunch

15:00 New DVCS results with CLAS12 at 10.6 GeV

While it has been known since the 60s that nucleons are composed of quarks and gluons, very little is understood about the mechanisms responsible for the emergence of nucleons from these partons. Generalized Parton Distributions (GPDs) provide the opportunity to obtain a 3-dimensional, tomographic picture of a nucleon. Moreover, GPDs are related to total angular momentum, mass and pressure distributions inside the nucleon. GPDs are experimentally accessible via the deeply virtual Compton scattering (DVCS), i.e. the absorption of a highly virtual photon by the proton and the subsequent emission of a high-energy photon.
At Jefferson Lab, the CLAS12 spectrometer has collected DVCS data on unpolarized proton with a longitudinally polarized 10.6-GeV electron beam in 2018. Central silicon and micromegas trackers within a 5T-solenoidal field surrounding the liquid hydrogen target are ideal to detect the recoil proton of a DVCS event. The forward detectors, placed in a toroidal magnetic field, detect the associated scattered electron and high energy photon. We will present results associated to two run periods, representing an unprecedented statistics and exploring a terra incognita at high Q${^2}$ and high x$_B$. After a careful subtraction of the background and a refined binning, a more detailed picture of the nucleon can be revealed by these new data.

Speaker: Dr maxime defurne (CEA-Saclay)

DIS2022.pdf

15:20 Deeply Virtual Compton Scattering at COMPASS

Generalized Parton Distributions are studied in exclusive reactions
like Deeply Virtual Compton Scattering (DVCS). In 2016 and 2017
DVCS was measured at COMPASS using 160 GeV positively and negatively
charged polarized muon beams provided by the M2 beamline of the SPS at CERN and
which was scattered off a 2.5 m long liquid hydrogen target. To perform an
exclusive measurement the target
was surrounded by a barrel-shaped time-of-flight system to detect
the recoiling target protons. The scattered muons and the produced real
photons were detected by the COMPASS spectrometer, which was supplemented by an additional electromagnetic calorimeter for the detection of large-angle photons.
The DVCS cross section is extracted separately for each beam charge and polarization to calculate the so called charge-spin cross section sum. Its dependence on the squared four-momentum transfer to the proton
is related to the transverse extension of partons in the proton covering the Bjorken $x$ domain of sea quarks. The talk will present the analysis method and preliminary
results of the 2016 run.

Speaker: Johannes Vincenzo Giarra (Johannes Gutenberg Universitaet Mainz (DE))

Giarra_DIS2022.pdf

15:40 Two loop corrections to the flavor-singlet vector coefficient function of DVCS

Motivated by the research program of the Electron Ion Collider,
we have calculated the two-loop (NNLO) flavor-singlet (vector) coefficient
function of deeply virtual compton scattering (DVCS).
Apart from the result and some technical aspects of the calculation,
I will present numerical estimates of the size of the NNLO
correction to the corresponding Compton form factors.

Speaker: Jakob Schönleber (University of Regensburg)

DVCS2lCF.pdf

16:00 Phenomenology of diphoton photoproduction at next to leading order

Authors: Oskar Grocholski, Bernard Pire, Pawel Sznajder, Lech Szymanowski, Jakub Wagner

Extraction of generalized parton distributions (GPDs) from experimental data requires us to consider various exclusive processes on hadrons. The most popular ones - such as DVCS, TCS, DVMP - have been already well studied at higher QCD order. In our recent works, we developed the NLO description (in strong coupling) of photoproduction of photon pairs with a large invariant mass on a nucleon target, which has some interesting features useful in possible experimental studies. Owing to the charge symmetry, the discussed process is sensitive to $\mathcal{C}$-odd combination of GPDs only. Moreover, the relevant partonic subprocess is $2\rightarrow 3$ reaction (unlike previous examples, which are $2\rightarrow 2$), which results in much richer kinematics.
In this talk, I will discuss the results of one-loop QCD computation at the leading twist, and describe the results of our recent phenomenological studies of photoproduction of photon pairs, performed using the PARTONS platform for the experimental conditions accessible to the JLab experiments. I will present numerical predictions for both proton and neutron targets obtained using various GPD models.

Speaker: Oskar Grocholski

Grocholski_DIS2022.pdf

16:20 Artificial neural network modelling of generalised parton distributions

We discuss the use of machine learning techniques in effectively nonparametric modelling of generalised parton distributions (GPDs) in view of their future extraction from experimental data. Current parameterisations of GPDs suffer from model dependency that lessens their impact on phenomenology and brings unknown systematics to the estimation of quantities like Mellin moments. The new strategy presented in this study allows to describe GPDs in a way fulfilling theory-driven constraints, keeping model dependency to a minimum. Getting a better grip on the control of systematic effects, our work will help the GPD phenomenology to achieve its maturity in the precision era commenced by the new generation of experiments.

Speaker: Paweł Sznajder (National Centre for Nuclear Research)

sznajder_dis0522.pdf

16:40 Coffee break

17:10 Proton mass decomposition in QCD

In QCD, the proton mass can be decomposed into contributions from quarks and gluons. But somewhat similar to the case of the proton spin, this decomposition is not unique. In this talk, we give an up-to-date review and comparison of different sum rules for the proton mass. We also discuss how future measurements at the EIC could further this field.

Speaker: Andreas Metz

DIS_proton_mass_Metz.pdf

DIS_proton_mass_Metz_proceedings.pdf

17:30 Constraining the Proton’s Gluon Helicity Distribution with Inclusive Jet and Dijet Measurements at STAR

A quantitative understanding of how gluonic spin contributes to the spin of the proton has been a central goal of the RHIC spin program. In polarized pp collisions, the large kinematic coverage of the Solenoidal Tracker At RHIC (STAR) provides sensitivity to gluons over a broad range in their momentum fraction x through the qg and gg scattering processes that dominate jet production at RHIC energies. The gluon helicity function, Δg( x), can be probed via measurements of the longitudinal double-spin asymmetry A_LL in inclusive jet and dijet production, which are vital input to global analyses. Inclusive jet results from STAR at mid-rapidity (|η| < 1) using 2009 pp data at √s = 200 GeV, when added to such analyses, indicated substantial positive polarization (i.e., aligned with the proton spin direction) for gluons with x > 0.05. Since then, higher statistics data sets were collected in 2015 at the same energy, while significantly larger data samples have been recorded at √s = 510 GeV in 2012 and 2013. In addition, new analyses have pushed the kinematic reach to higher pseudorapidities (up to η ∼ 1.8) and have been extended to study dijet production as well, all of which provide new and much needed constraints in the largely unexplored region x < 0.05. The status of these analyses and their potential impact on Δg( x) will be discussed.

Speaker: Scott Wissink

DeltaG DIS2022 Wissink final.pdf

17:50 Constraining gluon helicity distributions in proton

We perform the first simultaneous global QCD analysis of spin-averaged and spin-dependent parton distribution functions (PDFs), including single jet production data from unpolarized and polarized hadron collisions. We critically assess the impact of SU(3) flavor symmetry and PDF positivity assumptions on the quark and gluon helicity PDFs, and find strong bias from these, particularly on the gluon polarization. The simultaneous analysis allows for the first time extraction of individual helicity-aligned and antialigned PDFs with a consistent treatment of uncertainties.

Speaker: Yiyu Zhou (South China Normal University)

presentation.pdf

18:10 First analysis of world polarized SIDIS data with small-$x$ helicity evolution

We use small-$x$ helicity evolution equations to analyze the world polarized DIS and Semi-inclusive DIS (SIDIS) data. After successfully describing the $g_1$ structure function extracted from polarized DIS, we extend this analysis to the small-$x$ $g^h_1$ structure function measured in polarized SIDIS. The fit is performed through a Monte-Carlo analysis within the JAM global framework. Combining the DIS and SIDIS data we are able to extract the individual helicity PDFs for both the light quarks and light anti-quarks. The advantage of our approach is that our evolution predicts the small-$x$ behavior of these helicity distributions, allowing for a precise extrapolation of our helicity PDFs to smaller values of $x$, in the region that cannot be accessed experimentally. This brings us one step closer to resolving the proton spin problem.

Speaker: Daniel Adamiak (Ohio State University)

Daniel Adamiak DIS 2022 Slideshow.pdf

18:30 Precision Measurement of the Neutron Asymmetry $A_1^n$ at Large Bjorken $x$ at 12 GeV Jefferson Lab

The virtual photon asymmetry $A_1$ is one of the fundamental quantities that provide information on the spin structure of the nucleon. The value of $A_1$ at high $x_{Bj}$ is of particular interest because valence quarks dominate in this region, which makes it a relatively clean region to study the nucleon structure. Several theoretical calculations, including naive SU(6) quark model, relativistic constituent quark model (RCQM), perturbative QCD (pQCD), predicted the behavior for $A_1$ and the quark polarization in the high $x_{Bj}$ valence quark region. The $A_1^n$ experiment during the 6 GeV JLab era showed that $A_1^n$ turns positive at $x\sim 0.5$, while up to the highest measured $x$ value of 0.61 $\Delta d/d$ remains negative, in contrast to the pQCD prediction. Subsequent theoretical studies following the 6 GeV results claimed that quark orbital angular momentum could delay the upward turn of $\Delta d/d$ to higher $x_{Bj}$ or non-perturbative nature of the strong interaction could keep it negative all the way to $x_{Bj}=1$ as predicted in Schwinger-Dyson approach with di-quark model assumption. With the 12 GeV upgrade of JLab, a new experiment on $A_1^n$ (E12-06-110)$^1$ was carried out using a 10.4 GeV beam, a polarized $^3$He target, and the HMS and the Super-HMS (spectrometers) in Hall C. This measurement reached a deeper valence quark region: $x\sim 0.75$. When combined with the expected data from the upgraded CLAS12 experiment on the proton $A_1^p$, we will be able to reveal whether $\Delta d/d$ turns positive (as in pQCD) or remain negative at high $x$ (as in RCQM or Schwinger-Dyson/di-quark). We will present the physics of $A_1^n$ and report the analysis status for the $A_1^n$ experiment. Performance of the upgraded polarized $^3$He target will also be presented.

$^1$ This work is supported in part by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-FG02-94ER4084.

Speaker: Mingyu Chen (University of Virginia)

DIS_2022_Mingyu_Chen.pdf

09:20 → 18:50 WG6: Future Experiments: Session 1

Conveners: Alessandro Polini (Universita e INFN, Bologna (IT)), Michela Chiosso (University of Torino and INFN), Yulia Furletova

09:40 Overview on the LHeC and FCC-he: physics and accelerator

In this talk the current status and plans are presented on the LHeC, towards the new HEP strategy update in about 5 years time, on physics, with emphasis on the $eh-hh$ relation, on the machine, especially the IR, and further detector developments. The talk also covers FCC-he and refers to a separate presentation of the ERL facility PERLE. It is based on the comprehensive Conceptual Design Report update [1].

[1] P. Agostini et al. (LHeC Study Group), The Large Hadron-Electron Collider at the HL-LHC, J. Phys. G 48 (2021) 11, 110501, e-Print: 2007.14491 [hep-ex].

Speaker: Christian Schwanenberger (Deutsches Elektronen-Synchrotron (DE))

LHeC_FCCeh__Physics_Accelerator.pdf

10:00 Overview of the physics performance of the ECCE detector

An overview of the science programme accessible with the proposed ECCE detector at the future Electron-Ion Collider (EIC) will be presented. To this effect, results from complete ECCE GEANT4 simulation studies of physics observables will be shown. The selection of presented results cover the capabilities of the ECCE detector in addressing the origin of the nucleon spin, the three-dimensional structure of the nucleon, the study of saturation effects, and the study of the meson structure. Finally, some results on studies of precision Electroweak and beyond-the-Standard-Model Physics will also be discussed.

Speaker: Charlotte Van Hulse

dis22_charlotte.pdf

10:20 The Physics Potential of a TeV Muon-Ion Collider

The development of a TeV-scale muon accelerator and storage ring provides enormous scientific potential not only for a $\mu^+\mu^-$ collider, but also for deep inelastic scattering in a completely new regime when a TeV muon beam is collided with a hadron beam. For example, if the approved Electron-Ion Collider at BNL were eventually upgraded with a TeV muon beam replacing its low energy electron ring, a $Q^2$ reach of up to $10^6$ GeV$^2$ is accessible and a parton momentum fraction $x$ down to $1.0\times 10^{-5}$ can be probed. This coverage is equivalent to that of the proposed LHeC, although the facility at BNL offers the additional possibilities of polarized beams to study spin dependencies and a large variety of ion beams.

We report on studies of the physics potential at such muon-ion colliders that could be realized at the BNL facility as well as at other sites such as the CERN LHC. In particular, we summarize and contrast the kinematics in such high momentum muon-ion collisions with other collider proposals, and discuss the prospects for electroweak and QCD measurements. The sensitivity to very low values of $x$ will allow a careful study of the expected region of gluon saturation in nuclei. We also examine the potential for Higgs boson studies in muon-proton collisions through calculations of the production cross sections for different beam energies and polarizations, as well as show the kinematic distributions of the decay products and of the scattered lepton and parton. We also report on the sensitivity to some beyond Standard Model processes such as those involving leptoquarks that couple to muons and heavy quarks, where the cross sections for different leptoquark models and beam energies are calculated. Finally, we discuss some detector design considerations and the needed coverage and resolution for measurements. A common feature for the experiments at such a muon-ion collider facility is the need for a forward muon spectrometer.

Speaker: Darin Acosta (Rice University (US))

DIS-MuIC-Acosta2.pdf

DIS-MuIC-Acosta.pptx

10:40 The Future of CEBAF

The CEBAF accelerator at Jefferson Lab has been providing polarized electrons for high-impact nuclear and particle physics experiments for almost three decades. Accelerator upgrades providing polarization of the beam, increasing the beam energy, and increasing number of experimental end stations have paved the way to many new and successful experiments conducted at the lab. Studies are underway of potential future upgrades for the accelerator and the physics they would make possible. The considered upgrades include exciting topics such as doubling the luminosity of the accelerator, doubling the energy reach, and providing positron beams with a high degree of spin polarization. In this presentation I will discuss recent efforts to improve and expand the capabilities of CEBAF, highlighting some of the innovative ideas proposed while mentioning the challenges remaining to be solved.

Speaker: Reza Kazimi (Jefferson Lab)

Future_of_CEBAF_R_Kazimi_v20.pdf

Future_of_CEBAF_R_Kazimi_v20.pptx

11:00 Coffee break

11:30 The LHCspin project

The goal of LHCspin is to develop, in the next few years, innovative solutions and cutting-edge technologies to access spin physics in polarised fixed-target collisions at high energy, exploring the unique kinematic regime offered by LHC and exploiting new final states by means of the LHCb detector. The forward geometry of the LHCb spectrometer is perfectly suited for the reconstruction of particles produced in fixed-target collisions. This configuration, with centre of mass energies ranging from 115 GeV in p−p interactions to 72 GeV in heavy ion collisions, allows to cover a wide backward rapidity region, including the poorly explored high−x regime. With the instrumentation of the proposed target system, LHCb will become the first experiment simultaneously collecting unpolarised beam-beam collisions at 14 TeV and both unpolarised and polarised beam-target collisions. The status of the project is presented along with a selection of physics opportunities.

Speaker: Shinichi Okamura (Universita e INFN, Ferrara (IT))

proceeding_lhcspin_okamura_dis2022.pdf

slides_okamura_dis2022.pdf

11:50 QCD at FCC-ee

The Future Circular Collider with electron-positron beams (FCC-ee) will provide improvements of the precision measurement concerning Z, W, H, and top by a large factor over the present status. High precision with the run at the Z pole, where the instantaneous luminosity is expected to be five to six orders of magnitude larger than LEP, offers considerable improvements of the strong coupling constant determination. Examples of QCD measurements include the hadronic widths of the Z and W bosons.

Speaker: Eduardo Ploerer (University of Zurich (CH))

eploerer_DIS2022_Proceedings.pdf

eploerer_FCCee_DIS2022_final.pdf

12:10 The 3D structure of pions at future electron-ion colliders

Nowadays the study of hadron's structure is triggering ambitious efforts, both on the theretical and experimental side. The advent of new facilities such as the EIC or the EIcC is expected to be shed light on many of the still open questions about hadron’s complexity. This work takes advantage of the such situation to perform the first systematic feasibility study of accessing generalised parton distributions of the pion at an electron-ion collider through deeply virtual Compton scattering. Relying on state of the art models for pion GPDs fulfilling by construction all the theoretical properties required by QCD, we compute the amplitude for DVCS at EIC and EIcC kinematics. Predictions for the expected number of events and beam spin asymmetries are shown, demonstrating that gluon content gives the dominant contribution to the DVCS amplitude, modulating the expected number of events and observed beam spin asymmetries. Finally, through comparison with phenomenological models for pion GPDs we argue that DVCS might be accessible at the forthcoming electron-ion colliders or, in the worst case scenario, must yield crucial information about the origin of glue within pions.

Speaker: Jose Manuel Morgado Chávez (Universidad de Huelva)

SlidesDIS2022-JMMC.pdf

12:30 Signatures of gluon saturation in future DIS experiments

Discovering experimental signatures of gluon saturation is one of the major physics motivations behind the future nuclear-DIS facilities such as the Electron-Ion Collider. Probably the simplest observable to look for saturation effects is the inclusive structure function measurement, where the Bjorken-$x$ dependence can be predicted from the Color Glass Condensate framework by solving the Balitsky-Kovchegov (BK) small-$x$ evolution equation which includes non-linear saturation effects. On the other hand, in collinear factorization based approaches the DGLAP evolution can predict the virtuality ($Q^2$) dependence. As both the BK and DLGAP equations require non-perturbative initial conditions, distinguishing genuine BK and DGLAP effects must be done carefully.
We quantify in [1] the differences between the BK and DGLAP evolutions in proton and nuclear DIS structure functions in EIC and LHeC kinematics, and assess the capabilities of the future facilities in distinguishing between the DGLAP and BK dynamics, taking into the fact that there is uncertainty related to the non-perturbative initial condition. By reweighting PDFs to pseudodata generated with BK evolution we construct DGLAP evolved structure functions $F_2$ and $F_L$ which agree with the corresponding BK-evolved structure functions on a $Q^2_s(x)$ line in the $(x,Q^2)$ plane. By studying the deviations outside the $Q^2_s(x)$ line we can determine how fast DGLAP evolution differs from BK evolution.
For proton targets we find that the $F_2$ structure function needs to be measured at a few percent accuracy in order to distinguish the DGLAP and BK evolutions. For $F_L$ the differences are larger, up to $10\ \%$ in EIC kinematics and $40\ \%$ at the LHeC/FCC-he. With heavy nuclei, we also find significant deviation up to $10\ \%$ in case of $F_2$ structure function. As with proton targets, $F_L$ is much more sensitive observable to gluon saturation, with differences to BK evolved predictions being up to $20\ \%$ in EIC kinematics and $60\ \%$ at the LHeC/FCC-he.

References:
[1] N. Armesto, T. Lappi, H. Mäntysaari, H. Paukkunen, M. Tevio, in preparation

Speaker: Mirja Tevio

Tevio_DIS2022_WG6.pdf

12:50 Parton structure at the LHeC and FCC-he

The LHeC and the FCC-he are the cleanest, high resolution microscopes that the world can build in the nearer future. Through a combination of neutral and charged currents and heavy quark tagging, they will unfold the parton structure of the proton with full flavour decomposition and unprecedented precision. In this talk we will present the most recent studies on the determination of proton parton densities. We will also present the results on the determination of the strong coupling constant through the measurement of total and jet cross sections. Finally, we will also comment on diffraction, both inclusive and exclusive, as a tool to get more differential information on the proton.

Reference: P. Agostini et al. (LHeC Study Group), The Large Hadron-Electron Collider at the HL-LHC, J. Phys. G 48 (2021) 11, 110501, e-Print: 2007.14491 [hep-ex].

Speaker: Claire Gwenlan (University of Oxford (GB))

DIS22-LHeC-PDFs-Gwenlan.pdf

13:10 Lunch

15:00 Dark Sector searches at the intensity frontier

Many astrophysical observations as well as anomalies in processes involving electromagnetic currents (e.g. the muon anomalous magnetic moment) could be reconciled assuming the existence of a new kind of matter, not directly interacting with light, called Dark Matter (DM). While
gravitational effects of DM are quite well established, despite the tremendous efforts being devoted to reveal the nature of DM in terms of new elementary particles, no clear results have been obtained so far. Many experimental efforts are dedicated to direct detection of galactic DM, as well as to study the indirect effects of its presence. Due to the lack of results by ‘traditional’ DM searches, in the last few years the experimental activity extended to search for hints of DM produced at accelerators. Technological advances allow nowadays running high intensity beams of moderate energy well suited for these studies. According to some theories beyond the Standard Model (SM) Light Dark Matter (LDM ) (1-1000 MeV) can interact with SM matter via a new force, mediated by a heavy vector boson called A’ or ‘heavy photon’. Depending on the relative masses of the A’ and the DM particles, the A’ can decay to SM particles (‘visible’ decay) and/or to light DM states (‘invisible’ decay).
In this contribution, I will give an overview of the current LDM physics, focusing on experiments using high intensity electron and positron beams proposed to run in the next years at Jefferson Lab.

Speaker: Dr Marco Battaglieri (INFN-GE)

DISA2022-May22.pdf

15:20 Dark matter production with light mediator exchange at future e+e- colliders

One of the primary goals of the proposed future collider experiments is to search for dark matter (DM) particles using different experimental approaches. High energy e$^+$e$^-$ colliders offer unique possibility for the most general search based on the mono-photon signature. As any e$^+$e$^-$ scattering process can be accompanied by a hard photon emission from the initial state radiation, analysis of the energy spectrum and angular distributions of those photons can be used
to search for hard processes with invisible final state production and to test the nature and interactions of the DM particles.

Production of DM particles at the International Linear Collider (ILC) and Compact Linear Collider (CLIC) experiments was studied using dedicated simulation procedure developed for WHIZARD and the DELPHES fast simulation framework. Limits on the light DM production cross section in a generic model are set as a function of the mediator mass and width, and translated into the limits on the mediator coupling to electrons. If deviations from the Standard Model predictions are
observed, mediator mass, width and coupling structure can be constrained from the reconstructed mono-photon event distributions.

Speaker: Aleksander Zarnecki (University of Warsaw (PL))

dis2022_mono_photon_proceedings.pdf

zarnecki_dis2022_v3.pdf

15:40 New top and BSM Physics at the LHeC and FCC-he

The LHeC and the FCC-he offer fascinating, unique possibilities for measurement of top properties and discovering BSM physics in DIS, both due to their large centre-of-mass energies and high luminosities. In this talk we will review the most recent studies. We will revisit the determination of the top mass through inclusive measurements. In addition, we will address the possibilities for precise measurements of $Wtq$ and $\gamma tq$ couplings, and competitive searches for FCNC top couplings. We will show the prospects for observing extensions of the Higgs sectors both with charged and neutral scalars, anomalous Higgs couplings and exotic decays. Then we will discuss searches for R-parity conserving and violating supersymmetry both with prompt and long-lived particles, and of feeble interacting particles like sterile neutrinos, fermion triplets, dark photons and axion-like particles. Finally we will address anomalous couplings and searches for heavy resonances like leptoquarks and vector-like quarks, excited fermions and colour-octet leptons.

Reference: P. Agostini et al. (LHeC Study Group), The Large Hadron-Electron Collider at the HL-LHC, J. Phys. G 48 (2021) 11, 110501, e-Print: 2007.14491 [hep-ex].

Speaker: Oliver Fischer

DIS22_Fischer_Top_BSM.pdf

16:00 LUXE: A new experiment to study non-perturbative QED in electron-LASER and photon-LASER collisions

The LUXE experiment (LASER Und XFEL Experiment) is an experiment in planning at DESY Hamburg using the electron beam of the European XFEL. LUXE is intended to study collisions between a high-intensity optical laser pulse and 16.5 GeV electrons from the XFEL electron beam, as well as collisions between the LASER pulse and high-energy secondary photons. This will elucidate Quantum Electrodynamics (QED) at the strong-field frontier, where the electromagnetic field of the laser is above the Schwinger limit. In this regime, QED is non-perturbative. This manifests itself in the creation of physical electron-positron pairs from the QED vacuum, similar to Hawking radiation from black holes. LUXE intends to measure the positron production rate in an unprecedented LASER intensity regime. The experiment received a stage 0 critical approvement (CD0) from the DESY management and is in the process of preparing its technical design report (TDR). It is expected to start running in 2024/5. An overview of the LUXE experimental setup and its challenges and progress will be given, along with a discussion of the expected physics reach in the context of testing QED in the non-perturbative regime.

Speaker: Aharon Levy (Tel Aviv University (IL))

AL-DIS2022-LUXE copy.pdf

AL-DIS2022-LUXE copy.pptx

main.pdf

16:20 Scattering and Neutrino Detector at the LHC

SND@LHC is a compact and stand-alone experiment to perform measurements with neutrinos produced at the LHC in a hitherto unexplored pseudo-rapidity region of 7.2 < 𝜂 < 8.6, complementary to all the other experiments at the LHC. The experiment is to be located 480 m downstream of IP1 in the unused TI18 tunnel. The detector is composed of a hybrid system based on an 800 kg target mass of tungsten plates, interleaved with emulsion and electronic trackers, followed downstream by a calorimeter and a muon system. The configuration allows efficiently distinguishing between all three neutrino flavours, opening a unique opportunity to probe physics of heavy flavour production at the LHC in the region that is not accessible to ATLAS, CMS and LHCb. This region is of particular interest also for future circular colliders and for predictions of very high-energy atmospheric neutrinos. The detector concept is also well suited to searching for Feebly Interacting Particles via signatures of scattering in the detector target. In the first phase the detector will operate throughout LHC Run 3 to collect a total of 150 fb−1. The experiment was approved by the Research Board at CERN and it is completing its installation and commissioning phase. A new era of collider neutrino physics is just starting.

Speaker: Marco Dallavalle (Universita e INFN, Bologna (IT))

DIS2022_SND-LHC_MDV_20220503_3.pdf

16:40 Coffee break

17:10 Heavy Neutrinos at Future Linear e+e- Colliders

Neutrinos are probably the most mysterious particles of the Standard Model. The mass hierarchy and oscillations, as well as the nature of their antiparticles, are currently being studied in experiments around the world. Moreover, in many models of New Physics, baryon asymmetry or dark matter density in the universe are explained by introducing new species of neutrinos. Among others, heavy neutrinos of the Dirac or Majorana nature were proposed to solve problems persistent in the Standard Model. Such neutrinos with masses above the EW scale could be produced at future linear e+e- colliders, like the Compact LInear Collider (CLIC) or the International Linear Collider (ILC).

We studied the possibility of observing production and decays of heavy neutrinos in the qql final state at ILC running at 500 GeV and 1 TeV and CLIC running at 3 TeV. The analysis is based on the WHIZARD event generation and fast simulation of the detector response with DELPHES. Dirac and Majorana neutrinos with masses from 200 GeV to 3.2 TeV are considered. Estimated limits on the production cross sections and on the neutrino-lepton coupling are compared with the current limits coming from the LHC running at 13 TeV, as well as the expected future limits from hadron colliders. Obtained results are stricter than other limit estimates published so far.

Speaker: Mr Krzysztof Mekala

Mekala_DIS2022.pdf

17:30 Deeply virtual Compton scattering with polarized positrons : perspectives for Jefferson Lab

Positron beams play a crucial role in the experimental programs of the next generation of lepton accelerators. In the context of the hadron-physics program of Jefferson Lab (JLab), positron beams are complementary to electron beams in the quest for a precise understanding of the structure of nucleons. In particular, the deeply-virtual scattering of polarized and unpolarized electrons and positrons allows unambiguous separation of the different contributions to the cross section of the leptoproduction of photons and of lepton pairs, enabling an accurate determination of the nucleons’ Generalized Parton Distributions (GPDs).
This talk will present the experimental program, proposed for JLab, to measure deeply virtual Compton Scattering (DVCS, $eN \to eN\gamma$), on both the proton and the neutron, with the CLAS12 spectrometer and polarized positron and electron beams of 10.6 GeV. The proposed measurement of Double Deeply Virtual Compton Scattering (DDVCS) with the SOLID spectrometer will also be presented. These experimental configurations will provide a direct access to the real parts of combinations of Compton Form Factors (CFFs), which are, in turn, connected to GPDs. The combination of DVCS observables on neutron and proton targets is a necessary step to perform the flavor decomposition of the real parts of the H and E CFFs. DDVCS will provide the unique possibility to disentangle the x (average momentum fraction carried by the initial-final quark) dependence of the CFFs.

Speaker: Dr Silvia Niccolai (CNRS)

DIS2022_niccolai.pdf

17:50 A Future Muon-Ion Collider at Brookhaven National Laboratory

There has been significant discussion in the community regarding a future $\mu^+\mu^-$ collider. While such a facility is still decades away from realization, it is also understood that significant technological development and feasibility demonstrations are necessary at lower beam energies. Here we propose such a possibility coupled with a rich physics program. We propose a future Muon-Ion Collider that would serve as a natural extension to the EIC program currently planned in the 2030’s and 40’s. We envision this collider would be implemented as an upgrade to the EIC, with $\mu$ beam energies between 18 GeV and 200 GeV. In this presentation we discuss the physics reach of such a collider, which could reach $x \approx 10^{-5}$ with a luminosity approaching $10^{34}$ cm$^{-2}$ s$^{-1}$. We argue that the physics reach of such a program is excellent and comparable to the LHeC (some measurements would be beyond the reach of the EIC), and it will facilitate accelerator technology development for the future muon collider.

Funding acknowledgment: This material is based upon work supported by the National Science Foundation under Grant No. PHY 2012114, and the Center for Frontiers in Nuclear Science.

Speaker: Ethan Cline (Stony Brook University)

muon_Ion_Collider_at_BNL.pdf

mup.pdf

18:10 Upgrade of ATLAS Hadronic Tile Calorimeter for the High Luminosity LHC

The Tile Calorimeter (TileCal) is a sampling hadronic calorimeter covering the central region of the ATLAS experiment, with steel as absorber and plastic scintillators as active medium. The High-Luminosity phase of LHC, delivering five times the LHC nominal instantaneous luminosity, is expected to begin in 2029. TileCal will require new electronics to meet the requirements of a 1 MHz trigger, higher ambient radiation, and to ensure better performance under high pile-up conditions. Both the on- and off-detector TileCal electronics will be replaced during the shutdown of 2026-2028. PMT signals from every TileCal cell will be digitized and sent directly to the back-end electronics, where the signals are reconstructed, stored, and sent to the first level of trigger at a rate of 40 MHz. This will provide better precision of the calorimeter signals used by the trigger system and will allow the development of more complex trigger algorithms. The modular front-end electronics feature radiation-tolerant commercial off-the-shelf components and redundant design to minimise single points of failure. The timing, control and communication interface with the off-detector electronics is implemented with modern Field Programmable Gate Arrays (FPGAs) and high speed fibre optic links running up to 9.6 Gb/s. The TileCal upgrade program has included extensive R&D and test beam studies. A Demonstrator module with reverse compatibility with the existing system was inserted in ATLAS in August 2019 for testing in actual detector conditions. The ongoing developments for on- and off-detector systems, together with expected performance characteristics and results of test-beam campaigns with the electronics prototypes will be discussed.

Speaker: Tibor Zenis (Comenius University (SK))

ATL-TILECAL-PROC-2022-008.pdf

Zenis_Upgrade_ATLAS_Tile.pdf

18:30 KINEMATIC FITTING OF NEUTRAL CURRENT EVENTS IN DEEP INELASTIC ep COLLISIONS.

We present a technique to reconstruct the scaling variables defining ep deep inelastic scattering based on a kinematic fit. Most techniques in use rely only on two of the four available quantities(energy and angle of the electron and struck quark), while the kinematic fit uses all available information simultaneously. Initial state radiation is included in the framework. The fitting is performed in a Bayesian framework [1] and informative priors are used for the relevant quantities fitted. The method has been tested on a simulated neutral current ep sample at a center of mass energy of 318 GeV with $Q^2 >$ 400 $GeV^2$, spanning the $x >10^{−2}$ phase space. A significantly better resolution in the reconstruction of the scaling variables is achieved.

Speaker: Prof. Allen Caldwell (MPP)

KF-DIS.pdf

11:30 → 15:00 WG4: QCD with Heavy Flavours and Hadronic Final States: Jet Session 2: heavy-flavour jets

Conveners: Maria Vittoria Garzelli, Olga Evdokimov (University of Illinois at Chicago (US)), Xuan Li (Los Alamos National Laboratory)

11:30 Inclusive and heavy-flavour jet measurements in ALICE experiment

Measurement of inclusive untagged and heavy-flavour jet production in pp
collisions provides an important test of perturbative QCD and can help to
improve Monte Carlo generators. Jet measurements in p-Pb collisions enable
the study of cold nuclear effects, including the nuclear modification of the PDF.
Jet grooming algorithms reduce nonperturbative effects by removing soft wide-
angle radiation in a theoretically tractable manner.

In this contribution, ALICE measurements of untagged and heavy-flavour
jet production in pp and p–Pb collisions will be discussed. The pT -differential
spectra of untagged inclusive jet pT production at various collision energies, jet
radii R and centralities will be reported. The pT-differential cross-section of
beauty jets in pp and p–Pb at √sNN = 5.02 TeV will be shown. For charm-
tagged jets, the jet momentum fraction carried by D0 -meson, evidence for the
dead-cone effect and distributions of groomed observables (groomed jet radius,
momentum fraction, number of splittings) will be presented. Calculations based
on pQCD and various Monte Carlo generators will be confronted with the
experimental results.

Speaker: Sebastian Bysiak (Institute of Nuclear Physics Polish Academy of Sciences (PL))

sbysiak_jetsALICE.pdf

11:50 Production of heavy quark dijets in forward directions

We report on calculations of differential cross sections for $c \bar c$- and $b \bar b$-dijet production in $pp$-scattering at $\sqrt{s} = 13$ TeV in the $k_T$-factorization and hybrid-factorization approaches with different unintegrated parton distribution functions (uPDFs). We present distributions in transverse momentum and pseudorapidity of the leading jet, rapidity difference between the jets and the dijet invariant mass. Our results are compared to recent LHCb data on forward production of heavy flavour dijets, measured for the first time individually for both, charm and bottom flavours. We found that an agreement between the predictions and the data within the full $k_T$-factorization is strongly related to the modelling of the large-$x$ behaviour of the gluon uPDFs which is usually not well constrained. The problem may be avoided following the hybrid factorization approach. Then a good description of the measured distributions is obtained with the Parton-Branching, the Kimber-Martin-Ryskin, the Kutak-Sapeta and the Jung setA0 CCFM gluon uPDFs. We calculate also differential distributions for the ratio of $c \bar c$ and $b \bar b$ cross sections. In all cases we obtain the ratio close to 1 which is caused by the minimal condition on jet transverse momenta ($p_{T}^{\mathrm{jet}} > 20$ GeV) introduced in the experiment, that makes the heavy quark mass almost negligible. The LHCb experimental ratio seems a bit larger. We discuss potentially important for the ratio effect of $c$- or $b$-quark gluon radiative corrections. The found effect seems rather small. More refine calculation requires full simulation of $c$- and $b$-jets which goes beyond of the scope of the present study.

[1] R. Maciuła, R. Pasechnik, and A. Szczurek, a paper in preparation

Speaker: Antoni Szczurek

szczurek_dis2022.pdf

12:10 Investigating heavy-flavour jet properties via heavy-flavour particle correlations with ALICE

Jet-like correlation measurements involving heavy-flavour hadrons allow for comparisons of their production, propagation, and hadronization across different collision systems. Comparison of measurements performed in pp and p-Pb collisions can help to study the possible modification of the heavy-quark production and hadronization inside jets due to cold-nuclear-matter effects, while possible effects relative to the formation of the quark-gluon plasma can be studied by comparing measurements performed in Pb-Pb collision system with those in small systems. The measurement of heavy-flavour jets gives more direct access to the initial parton kinematics and can provide further constraints for heavy-quark energy loss models.

In this contribution, the measurement of azimuthal correlations between D-meson and charged particle in pp collisions at $\sqrt{s}=$ 5.02, 7, and 13 TeV, in p-Pb collisions at $\sqrt{s_{\rm{NN}}}=$ 5.02 TeV and the azimuthal correlations between heavy-flavour decay electrons and charged particle in pp collisions at $\sqrt{s}= 5.02$ TeV are presented. The D-meson tagged jets measurements in pp at $\sqrt{s}= 5.02$, and 13 TeV, in p-Pb and Pb-Pb collision at $\sqrt{s_{\rm{NN}}}= 5.02$ TeV, and the measurements of the fragmentation function and radial shape of jets containing a $\Lambda_{c}$ in pp collision at $\sqrt{s}= 13$ TeV with ALICE will be shown. The data are compared with simulations performed with different Monte Carlo event generators which can help to investigate the heavy-quark production and hadronization processes. We will also present an evaluation of the performance for $\rm{D^{0}-\bar{ D^{0}}}$ correlation studies based on a simulated analysis for ALICE3.

Speaker: Ravindra Singh (Indian Institute of Technology Indore (IN))

Copy of Ravindra_DIS2022-2.pdf

12:30 Identification of b-jets using QCD-inspired observables

One of the most common final state resulting from high-energy particle collisions features collimated sprays of hadrons. These so-called hadronic jets can be seeded
by particles with very different properties (e.g. from fragmentation, and subsequent hadronization, of very energetic partons or from the hadronic decays of heavy particles, such as the Higgs boson etc). Therefore, the correct identification of the origins of hadronic jets is a key aspect in particle physics.

In this talk I will discuss the issue of separating hadronic jets that contain bottom quarks (b-jets) from jets featuring light partons only. I discuss a recently proposed (2202.05082) b-tagging approach that exploits the application of QCD-inspired jet substructure observables such as one-dimensional jet angularities and the two-dimensional primary Lund plane and demonstrate that these quantities can be used as inputs to modern machine-learning algorithms to efficiently separate b-jets from light ones.

Speaker: Oleh Fedkevych

b_taging_cnn_dnn_proceedings.pdf

DIS_OFedkevych_22.pdf

13:10 Lunch

15:00 → 17:10 WG4: QCD with Heavy Flavours and Hadronic Final States: Jet Session 3: jet associated production

Conveners: Maria Vittoria Garzelli, Olga Evdokimov (University of Illinois at Chicago (US)), Xuan Li (Los Alamos National Laboratory)

15:00 QCD aspects with V+jets in CMS

The associated production of a vector bosons and jets constitutes an excellent environment to perform experimental tests of perturbative QCD. Inclusive and differential cross sections of vector bosons produced in association with jets at 13 TeV will be presented for various physics channels. Differential distributions as function of a broad range of kinematical observables are measured and compared to the cutting edge precision in QCD predictions.

Speakers: CMS collaboration, Elisabetta Gallo (DESY)

ElisabettaGallo_DIS2022_Vjets_CMS.pdf

15:20 Measurement of Z boson production in association with jets at ATLAS

Measurements of W/Z-boson production in association with jets are an important test of perturbative QCD prediction and also yield information about the parton distribution functions of the proton. This talk will present recent Z+jets results focusing on extreme phase-spaces with high pT jets as well as high pT heavy-flavour jets. The data are presented differentially and compared to next-to-leading order QCD calculations and to theoretical predictions provided by various Monte Carlo event generators.

Speakers: ATLAS Collaboration, Federico Sforza (University and INFN Genoa)

Measurements of Z boson production in association with jets at ATLAS - DIS 2022.pdf

15:40 Vector boson production with heavy flavours in CMS

The associated production of a vector bosons and jets coming from the hadronization of b, c quarks are a powerful experimental handle to study the heavy flavour aspects of pQCD. Several predictions including the effect of the heavy flavour mass can be tested and NLO precision can be achieved with physics comparisons to flavour schemes in generators. Inclusive and differential cross sections of vector bosons produced in association with heavy flavours at 13 TeV will be presented for various physics channels including Z+b, W+b, W+c, Z+c.

Speakers: CMS Collaboration, Elisabetta Gallo (DESY)

ElisabettaGallo_DIS2022_VHF_CMS.pdf

16:00 Probing hadronization with flavor correlations of leading particles in jets

I will discuss nonperturbative flavor correlations between pairs of leading and next-to-leading charged hadrons within jets at the Electron-Ion Collider (EIC). We introduce a charge correlation ratio observable $r_c$ that distinguishes same- and opposite-sign charged pairs. Using Monte Carlo simulations with different event generators, $r_c$ is examined as a function of various kinematic variables for different combinations of hadron species, and the feasibility of such measurements at the EIC is demonstrated. I will also discuss the correlation between leading hadrons and leading subjets which encodes the transition between perturbative and nonperturbative regimes. The precision hadronization study we propose will provide new tests of hadronization models and hopefully lead to improved quantitative, and perhaps eventually analytic, understanding of nonperturbative QCD dynamics.

Speaker: Dr Yang-Ting Chien (Georgia State University)

DIS_2022_Chien.pdf

16:20 Probing hadronization and jet substructure with leading particles in jet at H1

A momentum charge correlation ratio observable $r_{c}$, generalized from the balance function [1], is measured using data recorded with the H1 experiment at HERA during 2003 to 2007. This variable distinguishes between same-sign and opposite-sign charged particle pairs[2] in a jet. The average $r_{c}$ is studied for two configurations (prongs) of the leading particles in the jet, defined with the help of declustering in a recursive soft drop technique. When resolved as as a function of other kimenatic variables, such as the formation time, this probes the transition from non-perturbative to perturbative aspects of QCD. This sets the path for a novel way of studying jet substructure and the evoluation of partons in a jet. The data of $r_{c}$ at different prongs reveal differences between the first and subsequent splits. Data are confronted with predictions from various event generators.

H1prelim-22-032

[1] S. A. Bass, P. Danielewicz and S. Pratt, Phys. Rev. Lett. 85 (2000), PhysRevLett.85.2689 [nucl-th/0005044].
[2] Y. T. Chien, A. Deshpande, M. M. Mondal and G. Sterman, [arXiv:2109.15318].

Speaker: Mriganka Mouli Mondal (CFNS, Stony Brook University)

DIS2022_Mrig.pdf

H1_Charge_Correlations_Proc.pdf

16:40 Coffee-break

17:10 → 18:50 WG4: QCD with Heavy Flavours and Hadronic Final States: Jet Session 4: jets in DIS

Conveners: Maria Vittoria Garzelli, Olga Evdokimov (University of Illinois at Chicago (US)), Xuan Li (Los Alamos National Laboratory)

17:10 Azimuthal correlations in photoproduction and deep inelastic ep scattering at HERA

Collective behaviour of final-state hadrons, and multiparton interactions are studied in high-multiplicity $ep$ scattering at a centre-of-mass energy $\sqrt{s}=318$ GeV with the ZEUS detector at HERA. Two- and four-particle azimuthal correlations, as well as multiplicity, transverse momentum, and pseudorapidity distributions for charged-particle multiplicities $N_{\rm ch} \geq 20$ are measured. The dependence of two-particle correlations on the virtuality of the exchanged photon shows a clear transition from photoproduction to neutral current deep inelastic scattering. For the multiplicities studied, neither the measurements in photoproduction processes nor those in neutral current deep inelastic scattering indicate significant collective behaviour of the kind observed in high-multiplicity hadronic collisions at RHIC and the LHC. Comparisons of PYTHIA predictions with the measurements in photoproduction strongly indicate the presence of multiparton interactions from hadronic fluctuations of the exchanged photon.

Speakers: Achim Geiser (DESY), Achim Geiser (Deutsches Elektronen-Synchrotron (DE))

LongRangeZEUS2.pdf

17:30 First measurement of groomed events shapes in ep DIS using archived H1 data

Event shapes provide incisive probes of QCD, both its perturbative and non-perturbative aspects. Grooming techniques have been developed to separate perturbative from non-perturbative components of jets in a theoretically well-controlled way, and have been applied extensively to jet measurements in hadronic collisions. In this talk the first application of grooming techniques to event shape measurements at HERA is presented, utilizing archived electron-proton Deep Inelastic Scattering data from the H1 experiment. The analysis is based on the novel Centauro jet clustering algorithm, which is designed specifically for the event topologies of ep DIS collisions. Cross-section measurements of groomed event 1-jettiness and groomed invariant jet mass are shown. The measurements are compared to Monte Carlo models, and to a theoretical calculation based on Soft Collinear Effective Theory.

H1prelim-22-033

Speaker: Henry Klest

DIS22 Klest - H1GES Final.pdf

DIS22 Klest - H1GES Final.pptx

17:50 TMDs in dijet and heavy hadron pair production in SIDIS

We discuss the measurement of gluon transverse momentum distribution (TMD) in dijet and heavy hadron pair (HHP) production in semi-inclusive deep inelastic scattering. The factorization of these processes in position space shows the appearance of a specific new soft factor matrix element on top of angular and complex valued anomalous dimensions. We show in detail how these features can be treated consistently and we discuss a scale prescription for the evolution kernel of the dijet soft function. As a result we obtain phenomenological predictions for unpolarized and angular modulated cross-sections for the electron-ion collider (EIC) using current available information on unpolarized TMD.

Speaker: Rafael Fernandez del Castillo (Universidad Complutense de Madrid)

DIS2022.pdf

18:10 Are Jets Narrowed or Broadened in e+A SIDIS?

We compute the in-medium jet broadening $\langle p^2_\perp\rangle$ to leading order in energy in the opacity expansion. At leading order in $\alpha_s$ the elastic energy loss gives a jet broadening that grows with $\ln{E}$. The next-to-leading order in $\alpha_s$ result is a jet narrowing, due to destructive LPM interference effects, that grows with $\ln^2{E}$. We find that in the opacity expansion the jet broadening asymptotics are - unlike for the mean energy loss - extremely sensitive to the correct treatment of the finite kinematics of the problem; integrating over all emitted gluon transverse momenta leads to a prediction of jet broadening rather than narrowing. We compare the asymptotics from the opacity expansion to a recent twist-4 derivation of $\langle p^2_\perp\rangle$ and find a qualitative disagreement: the twist-4 derivation predicts a jet broadening while the opacity expansion method predicts a narrowing. Comparison with current jet measurements cannot distinguish between the broadening or narrowing predictions. We comment on the origin of the difference between the opacity expansion and twist-4 results.

Speaker: Matthew Sievert (University of Illinois at Urbana-Champaign)

Sievert.pdf

18:30 New insights on strong coupling extractions from Soft Collinear Effective Theory

I will discuss the application of Soft Collinear Effective Theory (SCET) to the extraction of the strong coupling constant from e+e- event shape distributions, where state-of-the-art results exhibit a few sigma discrepancy with respect to the PDG world average. After briefly introducing event shape distributions and the SCET resummation formalism we use to study them, I will then focus on the canonical 'Thrust' variable, and on the phenomenological treatment of non-perturbative effects stemming from the soft sector. In particular, I will show that equivalently well-defined schemes for combining perturbative resummed and fixed-order contributions together with non-perturbative effects (notably renormalon cancellations) can lead to significant shifts in the extracted values of the strong coupling, when studying two-parameter fits in the dijet region. I also hope to briefly discuss novel (non-)perturbative extraction opportunities using the 'Angularities' class of observables, which generalizes the Thrust variable.

Speaker: Jim Talbert

alphaS_DIS_JT.pdf

19:15 → 21:15 Poster session and Reception

Wednesday 4 May

08:40 → 19:10 WG5: Spin and 3D Structure: Session 2

Conveners: Qinghua Xu (Shandong University), Yoshiyuki Miyachi (Yamagata University (JP)), yoshitaka hatta (BNL)

09:20 Measurement of target spin (in)dependent asymmetries in dimuon production in pion-nucleon collisions at COMPASS

The study of the spin structure of the nucleon by measuring nucleon spin (in)dependent azimuthal asymmetries in Drell-Yan process is one of the main topics of the phase-II research programme of the COMPASS experiment (M2 beamline, SPS, CERN).
In 2015 and 2018 COMPASS performed Drell-Yan measurements using a 190 GeV $\pi^-$ beam interacting with a transversely polarized $NH_3$ and unpolarized nuclear targets. The angular coefficients \lambda, \mu and \nu that describe the unpolarized part of the Drell-Yan cross section have been extracted from the data collected with tungsten target. Obtained results provide important information to study various perturbative and non-perturbative QCD effects. Performed polarized measurements of the Sivers and other transverse azimuthal asymmetries in Drell-Yan provide a unique possibility to test predicted in QCD (pseudo-)universal features of related transverse momentum dependent parton distribution functions. Measurement of the same set of asymmetries in J/$\psi$ production gives access to the gluon parton distribution functions and may serve as an important input for the study of J/$\psi$ production mechanisms.
In this talk recent results from COMPASS Drell-Yan programme will be presented together with related measurements from other experiments and available model predictions.

Speaker: Dr Bakur Parsamyan (CERN, JINR and Turin section of INFN)

Parsamyan_DIS2022_DY.pdf

09:40 Observation of azimuthal angular decorrelation in dijet photoproduction in ultraperipheral lead-lead collisions at 5.02 TeV with the CMS experiment

Angular correlations present in dijet photoproduction are studied, for the first time, using ultraperipheral lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The second moment of the angular distribution, $\langle \cos(2\Phi) \rangle$, where $\Phi$ is the angle between the vector sum $\vec{Q}_\mathrm{T}$ and the vector difference $\vec{P}_\mathrm{T}$ of the transverse momentum vectors of the jets, is measured as a function of $\vec{Q}_\mathrm{T}$. This analysis amounts to the first, yet essential, step towards the extraction of the Wigner or Husimi gluon distributions, which are believed to be the most fundamental gluon distributions. It also introduces new techniques for the analysis of jet angular correlations in exclusive dijet events at colliders.

Speaker: Michael Murray (The Univ. of Kansas)

Murray_DIS2022v3.pdf

10:00 Modified TMD Factorization and Sub-leading Power Corrections

Factorization theorems are known to be extremely powerful tools in high-energy particle physics. Processes like SIDIS, Drell-Yan vector-boson production, Higgs-boson production through gluon fusion and $e^+e^-$ to jets and/or hadrons are just some examples of processes that have been thoroughly investigated by applying rigorous factorization formulae. Furthermore, if in these processes the transverse momentum $\textbf{q}_T$ of the vector boson or final-state hadrons is measured, in the limit of small $\textbf{q}_T$, leading-power transverse-momentum-dependent (TMD) factorization is an established tool to obtain further insight into the internal structure of hadrons (like spin and helicity distributions, sea quark contributions) and/or jets involved. However, in order to properly exploit increasingly precise experimental data, it is important to investigate sub-leading contributions. In this talk, we present a novel method to compute next-to-leading-power and next-to-next-leading-power contributions to TMD cross sections. In the specific example of a Drell-Yan process, we show how our analytic results allow us to achieve next-to-next-to-leading logarithmic (NNLL) resummation, recover both the leading-power TMD factorization and collinear factorization expressions up to next-to-next-to-leading order in the small $\textbf{q}_T$ limit and provide a description of the cross section valid also at intermediate $\textbf{q}_T$. The implications for the phenomenological extraction of TMDPDFs are also discussed.

Speaker: Sergio Leal Gómez (Universität Wien)

Leal_Gomez_DIS_2022.pdf

10:20 Power corrections in semi-inclusive DIS

Semi-inclusive DIS is a natural process for the measurement of transverse momentum dependent distributions. While current fits and analysis use cross section at leading power in the ratio of transverse momenta and center of mass energy, we have computed and factorized the cross section at next-to-leading power, opening the way to a finer set of studies. The proof are done using the background-field method and the evolution of operators is also calculated.

Speaker: Alexey Vladimirov

Pow_Vladimirov.pdf

10:40 Phenomenology of gluon TMDs from eta_b,c production

In this talk we present the potential of $\eta_{b,c}$ production from hadronic collisions to access the gluon TMD PDFs. In particular, we explore the phenomenology of the unpolarized and linearly polarized gluon TMD PDF in unpolarized collisions for different kinematic settings, and the potential of a fixed-target experiment at the LHC to access T-odd distributions such as the gluon Sivers TMD PDF.

Speaker: Francesco Giovanni Celiberto (ECT*/FBK Trento & INFN-TIFPA)

proceeding_Celiberto_DIS_2022_eta_Q_gluon_TMDs.pdf

talk_DIS_2022_Celiberto_gluon_TMDs_etaQ.pdf

11:00 Coffee break

11:30 Measurement of Direct Photon Cross Section and Double Helicity Asymmetry at $\sqrt{s}$ = 510 GeV in $\vec{p}+\vec{p}$ Collisions at PHENIX

The longitudinal spin decomposition of the proton provides key information about its structure. While the quark spin contribution was well constrained by the polarized deep inelastic scattering (DIS), the gluon spin contribution remains less known. Direct photon, jet, and charged pion production in the longitudinally polarized proton ($\vec{p}+\vec{p}$) collisions can probe the gluon spin at leading order. Compared with hadron production, direct photon production is the most ``clean'' channel since there is little fragmentation involved. The Relativistic Heavy Ion Collider (RHIC) is the only collider that is capable of producing two longitudinal polarized proton beams. The RHIC run of year 2013 provides the largest integrated luminosity (155 pb$^{-1}$) in $\vec{p}+\vec{p}$ collisions. The Electromagnetic Calorimeter at PHENIX has fine granularity to separate the two $\pi^0$ decay photons up to $\pi^0$ transverse momentum $p_T$ of 12 GeV/c. The shower profile analysis further extends the $\gamma/\pi^0$ discrimination up to 30 GeV/c. In this talk, I will present the direct photon cross section and double helicity asymmetry ($A_{LL}$) for photon $p_T$ of 6--30 GeV/c and 6--20 GeV/c, respectively. When included in future global analyses, our results will provide an independent constraint on the gluon spin contribution to the proton spin.

Speaker: Dr Zhongling Ji (UCLA)

slides.pdf

11:50 Observable for gluon orbital angular momentum

By considering double spin asymmetry (DSA) in exclusive dijet production in $ep$ collisions, we demonstrate for the first time that the $cos(\phi)$ angular correlation between the scattered electron and proton is a direct probe of the gluon orbital angular momentum and its interplay with the gluon helicity. We also make an estimate of the DSA for typical kinematics of the future Electron Ion Collider.

Speaker: Shohini Bhattacharya (Brookhaven National Laboratory)

DIS2022_Shohini.pdf

12:10 Illuminating the nucleon spin

I will discuss the extension of the nucleon spin sum rule to QCD×QED. I will present the QED corrections to the evolution of the quark and gluon helicity and orbital-angular-momentum (OAM) distributions, which are calculated for the first time, and discuss the necessary inclusion of photon and lepton helicity and OAM distributions.

Speaker: Miguel Echevarria (University of the Basque Country UPV/EHU)

Echevarria-DIS2022.pdf

12:30 Proton spin, topology and confinement: lessons from $QCD_2$.

We investigate the relation between the topology of a nucleon and its spin composition. We approach this question in 1+1 dimensional single-flavor QCD with a large number of color. In this limit the theory can be shown to be dual to the exactly solvable sine-Gordon model. The spectrum of baryons and mesons is known analytically, and the baryon is a topological kink of the sine-Gordon model. Using the method of solitonic constituents we construct the state of the baryon and extract its $g_1$ structure function. Due to the topological nature of the baryon state this structure function is enhanced at low Bjorken $x$. We propose this enhancement as an experimental probe of the topological structure of the nucleon state.

Speaker: David Frenklakh (Stony Brook University)

David Frenklakh Proton spin lessons from QCD2.pdf

DIS Proceedings Frenklakh.pdf

12:50 Phenomenological analysis of the scalar PDF.

Seven years after the preliminary data were made available, the CLAS collaboration published both CLAS and CLAS12 results on the beam-spin asymmetry in semi-inclusive dihadron production off proton target. We present the phenomenological extraction of the associated twist-3 collinear PDF, e(x), made possible through the analysis of dihadron fragmentation function. We will discuss the extent to which our analysis shows that this collinear twist-3 PDF is non zero.

Speaker: Aurore Courtoy (Instituto de Física, UNAM)

laex_DIS_22.pdf

13:10 Lunch

15:00 Deeply virtual Compton scattering cross sections at high Bjorken x​

Generalized Parton Distribution (GPDs) are universal functions which provide a comprehensive description of hadron properties in terms of quarks and gluons. Deeply Virtual Compton Scattering (DVCS) is the simplest process involving GPDs. In this talk, we will present the latest $ep \to e p \gamma$ cross sections obtained from Jlab Hall A data at three values of the Bjorken variable $x_B$. In this reaction, the photon can be emitted by a quark inside the proton (DVCS process) or by the incoming or the scattered electron (BH process). The Fourier harmonics of the $ep \to e p \gamma$ cross section can then be expressed respectively as a function of linear (from the BH-DVCS interference) and bilinear (from the DVCS process) combinations of GPD convolutions called Compton form factors (CFFs). Using the most accurate analytic expression of the $ep \to e p \gamma$ cross section we will show the first experimental extraction of all four helicity-conserving CFFs. The large number of high statistics experimental bins in the present data allows a sensitivity to some very poorly known CFFs.

Speaker: Charles Hyde (Old Dominion University)

DIS2022-HallA-DVCS.pdf

15:20 Timelike Compton Scattering at ATHENA and the Electron-Ion Collider

The Electron-Ion Collider (EIC), to be built at Brookhaven National Lab within this decade, will provide high-precision access to the gluon and sea-quark dominated region of the nucleon. With luminosities of $10^{33-34}$ cm$^{-2}$s$^{-1}$, centre of mass energies 20-140 GeV, highly polarised electron and proton / light-ion beams and hermetic detectors, the collider will enable measurements of rare, exclusive processes in a very large, previously-unchartered region of the nucleon phase space. One such process is Timelike Compton Scattering (TCS), in which a real photon scatters from a quark within a nucleon and a high-virtuality photon is released as a result, splitting into lepton pairs that can be detected. TCS gives access to Generalised Parton Distributions (GPDs), which can be interpreted as relating transverse position of partons to their longitudinal momentum. GPDs, which yield 3D tomographic images of the nucleon, map out its pressure distribution and shed light on the contribution of orbital angular momentum to nucleon spin, are the focus of much experimental effort in electron scattering, but they are currently minimally constrained far below the valence region. We present a study of the EIC potential for measurements of TCS in a wide range of phase-space, with a focus on full simulations for ATHENA (A Totally Hermetic Electron-Nucleus Apparatus), one of the proposed EIC detectors.

Speaker: Daria Sokhan (CEA Saclay / Glasgow U.)

DIS2022_TCSatEIC_DariaSokhan.pdf

15:40 Recoil proton polarization as a window to Compton Form Factor E in a DVCS measurement

The proton structure can be parameterized through Generalized Parton Distributions (GPDs) - a formalism that describes exclusive processes and allows to perform tomography of the nucleon. Measurements of exclusive processes, such as Deeply Virtual Compton Scattering (DVCS), are sensitive to complex integrals of GPDs, known as Compton Form Factors (CFFs). To gain access to the elusive CFF E for the proton, the common approach is to perform a measurement using a transversely polarized hydrogen target. This study presents an alternative approach, based on the measurement of the DVCS recoil proton polarization from an unpolarized target. This method has the advantage of allowing for higher beam currents and thus higher luminosity. A feasibility study is performed in the context of Jefferson Lab.

Speaker: Olga Bessidskaia Bylund (CEA Paris-Saclay)

proceedings_RPP.pdf

RecoilProtonPolarization.pdf

16:00 Exclusive massive photon-pair production in pion-nucleon collisions for extracting generalized parton distributions

We show that exclusive massive photon-pair production in pion-nucleon collisions can be systematically studied in terms of QCD factorization approach if the photon's transverse momentum with respect to the colliding pion $q_T\gg\Lambda_{\rm QCD}$. We demonstrate that leading power non-perturbative contributions to the scattering amplitudes of this exclusive process are process-independent and can be systematically factorized into universal pion's distribution amplitudes (DAs) and nucleon's generalized parton distributions (GPDs), which are convoluted with corresponding infrared safe and perturbatively calculable short-distance hard parts. The correction to this factorized expression is suppressed by powers of $1/q_T$. We also demonstrate quantitatively that this new type of exclusive processes is not only complementary to existing processes for extracting GPDs, but also capable of providing an enhanced sensitivity to the momentum fraction $x$-dependence of both DAs and GPDs.

Speaker: Zhite Yu

DIS2022_ZhiteYu.pdf

16:20 Kinematical higher twist corrections in $\gamma^* + \gamma \rightarrow M_1+ M_2$

Generalized distribution amplitudes (GDAs) are the s-t crossing quantities of generalized parton distributions (GPDs), which can be measured in the process of $\gamma^* + \gamma \rightarrow M_1+ M_2$. In 2016, the Belle Collaboration released the measurements of differential cross section for $\gamma^* + \gamma \rightarrow \pi+ \pi$, from which the pion GDAs were extracted by using the leading-twist amplitude. Given the kinematics of Belle measurements, higher-twist contributions of order $s/Q^2$ and $m^2/Q^2$ should also be important in the cross section. Recently, a separation of kinematic and dynamical contributions in the operator product of two electromagnetic currents was proven, and the kinematic corrections of order $t/Q^2$ and $m^2/Q^2$ were estimated for Deeply Virtual Compton Scattering (DVCS) up to twist 4. In this work, we apply similar techniques to the process of $\gamma^* + \gamma \rightarrow M_1+ M_2$. We calculate the kinematic contributions where only the leading-twist GDA is involved, and show the size of the kinematic contributions in comparison with the leading-twist amplitude numerically. Since Belle II collaboration just started taking data at the Super KEKB with a much higher luminosity, precise measurements of $\gamma^* + \gamma \rightarrow M_1+ M_2$ are expected in the near future. In this case, the accurate description of the amplitudes for the GDA study requires the inclusion of kinematic contributions up to twist 4. Moreover, our work will also impact the studies on the energy-momentum tensor (EMT) in QCD, as the GDAs can provide us a good alternative way for constraining the EMT form factors of hadrons.

Speaker: Qintao Song (École Polytechnique)

DIS-talk.pdf

GDA-DIS-proceedings.pdf

16:40 Coffee break

17:10 Renormalization of collinear and TMD parton densities

I will discuss recent work on the issues that arise when dealing with ultraviolet renormalization of both collinear and TMD Parton densities. In particulars, I will discuss how some commonly assumed properties like positivity can be violated in standard schemes. I will discuss the ways that using TMD parton densities can help even when dealing with collinear pdfs.

Speaker: Dr Ted Rogers (Old Dominion University/Jefferson Lab)

DIS_2022.pdf

17:30 Jet azimuthal anisotropy in ep collisions

We study back-to-back lepton-jet production in lepton-proton collisions. This process defines two azimuthal angles, the transverse momentum imbalance $q_T$ of the lepton and the jet, and the azimuthal angle of the jet transverse momentum itself. In this work, we study the azimuthal anisotropy for the azimuthal angle difference φ between these two angles. In particular, we provide the theoretical origins for these azimuthal dependence from a factorization formalism derived within the SCET framework. In addition, we find that the directed flow component related to cos($\phi$) azimuthal asymmetry is dominant. We present the numerical results of such azimuthal anisotropy for both EIC and HERA kinematics with Pythia simulations, showing that these are promising observables for studying lepton-jet correlations in future experiments.

Speaker: Fanyi Zhao (UCLA)

dis2022_Fanyi.pdf

proceeding_FanyiZhao.pdf

17:50 Independent amplitudes in the quark and antiquark correlators and TMDs in the covariant parton model

Covariant parton model is a generalization of the Feyman's parton model which does not prefer any special reference system. Within the framework of covariant parton model, we study the properties of the quark and antiquark correlators determined by the equations of motion of the free partons, and derive the polarization vectors for quarks and antiquarks in mixed-spin and pure-spin states. We show that for partons in the pure-spin state, there is only one polarized and one unpolarized amplitude in each of the quark and antiquark correlator.

Speaker: Fatma Pinar Aslan

18:10 EpIC: a Monte Carlo generator for exclusive processes

Recently, exclusive processes have gained increasing attention. Part of this interest comes from the open questions of how the spin of the proton is decomposed into the intrinsic spin and the orbital motions of the constituent parts, along with the possibility of obtaining energy-momentum densities through exclusive processes. In this talk, we present the EpIC Monte Carlo event generator for exclusive processes. By utilizing the PARTONS framework, the EpIC generator offers a flexible structure and a variety of model options which make it an attractive tool for the community. Additionally, the EpIC generator includes first-order radiative corrections in its architecture. Consequently, EpIC offers a comprehensive set of features that will enable the community to study nucleon structure in more depth through impact studies on future electron-ion colliders.

Speaker: Kemal Tezgin

DIS_2022.pdf

18:30 3D EMT distributions as an Abel image of 2D EMT distributions on the light front

The matrix elements of the energy momentum tensor (EMT) between plane wave states define gravitational form factors (GFFs) which provide information about spatial distribution of energy, momentum and angular momentum. The Druck gravitational form factor is related to the mechanical stability of the nucleon and gives information about the spatial distributions of the forces inside the hadron. In this work we study the GFFs in the framework of the light front quark diquark model (LFQDM). The model has been successful to derive various properties of protons. We investigate the three dimensional spatial distributions of protons as an Abel image of 2D distributions in LFQDM. We explicitly show the global and local stability conditions which are satisfied by both 2D and 3D distributions in LFQDM. We compare our results with chiral quark soliton model and lattice data.

Speaker: POONAM CHOUDHARY (IIT Kanpur)

Poonam_DIS_2022_Proceeding.pdf

POONAM_DIS2022-TALK.pdf

18:50 Hard exclusive $\pi^{-}\Delta^{++}$ production off the proton with CLAS12 at JLAB

Hard exclusive pion production is a well established tool to study Generalized Parton Distributions (GPDs). During the last decade, extensive studies have been performed on hard exclusive $\pi^{0}$ and $\pi^{+}$ production off the proton. However, hard exclusive $\pi^{-}$ production off the proton is so far nearly unexplored. It can be described based on $N\rightarrow\Delta^{++}$ transition GPDs which can help us to gain insights into the 3D structure of the p to Δ transition. The talk will present a study of the polarized cross section ratio $\sigma_{LT’}/\sigma_0$ from hard exclusive $\pi^{-}$ electro-production off an un-polarized hydrogen target in the forward kinematic regime ($-t/Q^2$ << 1) based on beam-spin asymmetry measurements with CLAS12 at JLAB. The results will be compared to previous studies on hard exclusive $\pi^{0}$ and $\pi^{+}$ production, which show an opposite sign of the cross section ratio, and discussed in the context of a GPD and transition GPD based description.

Speaker: Dr Stefan Diehl

Diehl_DIS_2022_pimdelta.pdf

09:00 → 19:10 WG3: Electroweak Physics and Beyond the Standard Model: Session 2

Conveners: Adam Orion Martin (University of Notre Dame (US)), Heather Gray (UC Berkeley/LBNL), Heidi Angelika Rzehak

09:20 Measurements of light-by-light scattering, Breit-Wheeler e+e- production, and searches for axion-like particles in PbPb collisions at $\sqrt{s_{_{\mathrm{NN}}}} = 5.02$ TeV

Ultraperipheral lead-lead collisions at $\sqrt{s_{_{\mathrm{NN}}}} = 5.02$ TeV produce very large photon fluxes that provide the conditions to study photon-photon fusion processes in phase space regions inaccessible with proton-proton data. Measurements of light-by-light ( LbL) scattering and e+e- (Breit-Wheeler) production in ultraperipheral PbPb collisions with data collected during the 2015 and 2018 LHC runs at CMS will be presented, corresponding to integrated luminosities of about $0.4\,\textrm{nb}^{-1}$ and $1.6\,\textrm{nb}^{-1}$, respectively. The LbL study allows also to carry out competitive searches for axion-like particles (ALPs), decaying into a pair of photons, over the mass range $m_a $= 5--100 GeV.

Speaker: Ruchi Chudasama (Tata Inst. of Fundamental Research (IN))

Ruchi_DIS_2022.pdf

09:40 First measurement of the $\gamma\gamma\to\tau\tau$ production in PbPb collisions with the CMS experiment

Ultraperipheral lead-lead collisions at $\sqrt{s_{_{\mathrm{NN}}}} = 5.02$ TeV produce very large photon fluxes that fundamental quantum-mechanical processes can be observed. In this presentation, the first observation of the $\tau$ lepton production in ultraperipheral PbPb collision data collected by CMS at LHC is reported. This measurement paves the way for the determination of the anomalous electromagnetic moments of the $\tau$ lepton, which currently is poorly constrained.

Speaker: Georgios Krintiras (The University of Kansas (US))

DIS22_Proceedings_GKK.pdf

DIS_ GKK.pdf

10:00 ATLAS measurements of photon-photon fusion processes in Pb+Pb collisions

Relativistic heavy-ion beams at the LHC are accompanied by a large flux of equivalent photons, leading to multiple photon-induced processes. This talk presents a series of measurements of such processes performed by the ATLAS Collaboration. New measurements of exclusive dilepton production (electron, muon, and tau pairs) are discussed. These processes provide strong constraints on the nuclear photon flux and its dependence on the impact parameter and photon energy. In particular, measurements of the cross-sections in the presence of forward neutrons provide an additional experimental handle on the impact parameter range sampled in the observed events. Furthermore, the tau-pair production measurements can constrain the tau lepton's anomalous magnetic dipole moment. High statistics measurements of light-by-light scattering shown in this talk provide a precise and unique opportunity to investigate extensions of the Standard Model, such as the presence of axion-like particles. Presented measurements of muon pairs produced via two-photon scattering processes in hadronic Pb+Pb collisions provide a novel test of strong-field QED and can be a potentially sensitive electromagnetic probe of the quark-gluon plasma. These include the dependence of the cross-section and angular correlation on the mean-pT of the dimuon pair, the rapidity separation between the muons, and the angle that the pair makes with the second-order event-plane. Presented results are further compared with recent theory calculations.

Speaker: Iwona Grabowska-Bold (AGH University of Science and Technology (PL))

DIS2022-GammaGammaAtlas-052022.pdf

DIS2022Proceedings-IwonaGrabowskaBold.pdf

10:20 Photon PDF within the CT18 global analysis

Building upon the most recent CT18 global fit, we present a new set of parton distribution functions including the photon content of the proton based on an application of the LUX formalism. In this work, we explore two principal variations of the LUX ansatz. In one approach, which we designate "CT18lux," the photon PDF is calculated directly using the LUX formula for all scales, $\mu$. In an alternative realization, "CT18qed," we instead initialize the photon PDF in terms of the LUX formulation at a lower scale, $\mu\sim\mu_0$ ​, and evolve to higher scales with a combined QED+QCD kernel at $O(\alpha)$, $O(\alpha\alpha_s)$, $O(\alpha^2)$. While we find these two approaches generally agree, especially at intermediate $x$ $(10^{-3}

Speakers: C.-P. Yuan (Michigan State University), Keping Xie (University of Pittsburgh), Carl Schmidt (Michigan State University), Mengshi Yan (Peking University), TIMOTHY J HOBBS (Fermi National Accelerator Laboratory), Tie-Jiun Hou (Northeastern University, Shenyang)

CT18QED_DIS2022.pdf

10:40 QED parton distribution functions in the MSHT20 fit

We present the MSHT20qed set of parton distribution functions (PDFs). These are obtained from the MSHT20 global analysis via a refit including QED corrections to the DGLAP evolution at ${\cal O}(\alpha),{\cal O}(\alpha\alpha_S)$ and ${\cal O}(\alpha^2)$, and containing the photon PDF of the proton. As in the previous MMHT15qed study we use an input distribution for the photon that is derived from the LUXqed formulation, and find good consistency for the photon PDF with that of MMHT15qed, as well as with other recent sets. We also present a set of QED corrected neutron PDFs and accompanying photon distribution, and provide the photon PDF of the nucleons separated into elastic and inelastic contributions. We assess the general expectations for the impact of photon--initiated (PI) corrections to processes entering PDF fits, and review the effect of QED corrections on the other partons and on the fit quality, where electroweak corrections (including PI production) are appropriately added to the cross sections wherever possible. We explore the phenomenological implications of this set by comparing to a variety of benchmark cross sections, finding small but significant corrections due to the inclusion of QED effects in the PDFs.

Speaker: Dr Lucian Harland-Lang (University of Oxford)

lhl_gam_DIS.pdf

11:00 Coffee break

11:30 Modelling W boson pair production with rapidity gaps at the LHC

In this talk we will present a new calculation of $W^+ W^-$ production in the semi--exclusive channel, that is either with intact outgoing protons or rapidity gaps present in the final state, and with no colour flow between the colliding protons. This study provides the first complete prediction of the $W^+ W^-$ semi--exclusive cross section, as well as the breakdown between elastic and proton dissociative channels. It combines the structure function calculation for a precise modelling of the region of low momentum transfers with a parton--level calculation in the region of high momentum transfers. The survival factor probability of no additional proton--proton interactions is fully accounted for, including its kinematic and process dependence. We analyse in detail the role that the pure photon--initiated ($\gamma\gamma \to W^+ W^-$) subprocess plays, a comparison that is only viable by working in the electroweak axial gauge. In this way, we find that the dominance of this is not complete in the proton dissociative cases, although once $Z$--initiated production is included a significantly better matching to the complete calculation is achieved. A direct consequence of this is that the relative elastic, single and double dissociative fractions are in general different in comparison to the case of lepton pair production. We present a direct comparison to the recent ATLAS data on semi--exclusive $W^+ W^-$ production, finding excellent agreement within uncertainties. Our calculation is provided in the publicly available \texttt{SuperChic 4.1} Monte Carlo (MC) generator, and can be passed to a general purpose MC for showering and hadronization of the final state.

Speaker: Dr Lucian Harland-Lang (University of Oxford)

lhl_WW_DIS.pdf

11:50 Recent Standard Model measurements with the CMS detector

This talk reviews the most recent results in the study of standard model physics data analysis with the data collected by the CMS Collaboration.

Speaker: Santiago Folgueras (Universidad de Oviedo (ES))

SMRecentResults_Folgueras_v1.pdf

12:10 W mass measurement and electroweak searches at LHCb

The LHCb experiment covers the forward region of proton-proton collisions, and it can improve the current electroweak landscape by studying the production of electroweak bosons in this phase space complementary to ATLAS and CMS. In this talk, an overview of the wide LHCb electroweak measurement program will be presented. This includes the recent measurement of the W boson mass.

Speaker: Miguel Ramos Pernas (University of Warwick (GB))

Miguel_Ramos_Pernas_DIS_2022.pdf

12:30 General heavy-flavor mass scheme for charged-current DIS at NNLO and beyond

Incompleteness in current knowledge of neutrino interactions with nuclear matter imposes a primary limitation in searches for leptonic CP violation carried out at long-baseline neutrino experiments like DUNE. In this talk, we summarize a recent computation that elevates the theoretical accuracy to next-to-next-to-leading order in QCD for charged-current DIS processes relevant for ongoing and future neutrino programs as well as the Electron-Ion Collider. Mass-dependent quark contributions are consistently included across a wide range of momentum transfers in the simplified-ACOT-$\chi$ general-mass scheme. When appropriate, we further include next-to-next-to-next-to-leading order corrections in the zero-mass scheme. We highlight theoretical predictions for neutrino experiments and the EIC, demonstrating that our approach reduces perturbative uncertainties to $\sim\!1\%$; this level of precision will be valuable for achieving target sensitivities at future charged-current DIS measurements to signatures of leptonic mixing, CP violation, and the partonic substructure of hadrons and nuclei.

Speaker: Dr TIMOTHY J HOBBS (Fermi National Accelerator Laboratory)

DIS22_Hobbs_upload.pdf

12:50 The Drell-Yan $q_T$ Spectrum and Its Uncertainty at N$^3$LL$'$

We provide state-of-the art SCETlib predictions for the $W$ and $Z/\gamma^*$ transverse-momentum ($q_T$) distributions at the LHC at complete three-loop order in resummed perturbation theory (N$^3$LL$'$) and matched to available fixed order. We compare our predictions to high-precision measurements by the ATLAS and CMS experiments. We pay particular attention to the estimation of theory uncertainties via profile scale variations in such a way that perturbative uncertainties due to PDF evolution, other perturbative resummation uncertainties, and nonperturbative uncertainties for $q_T\to 0$ are cleanly disentangled. We also study the dependence on PDFs and their parametric uncertainties, focussing on the region $q_T \leq 40$ GeV. In this region, the dominant resummed contributions are fully known to three loops while remaining fixed-order corrections are power suppressed. In principle, this allows for future extractions of PDFs at genuine three-loop order from high-precision measurements in this region.

Speaker: Johannes Michel (MIT CTP)

Michel_DIS_2022-05-04.pdf

13:10 Lunch

16:40 Coffee break

18:10 New physics results with the CMS Precision Proton Spectrometer

The Precision Proton Spectrometer (PPS) is a new subdetector of CMS introduced for the LHC Run 2, which provides a powerful tool for advancement of BSM searches. The talk will present the new results on exclusive diphoton, ttbar, Z+X, and diboson production explored with with PPS, illustrating the unique sensitivity which can be achieved using proton tagging.

Speaker: Enrico Robutti (INFN e Universita Genova (IT))

robutti_DIS2022.pdf

18:30 Recent searches for new phenomena with the ATLAS detector

Many theories beyond the Standard Model (BSM) have been proposed to address several of the Standard Model shortcomings, such as the origin of dark matter and neutrino masses, the fine-tuning of the Higgs Boson mass, or the observed pattern of masses and mixing angles in the quark and lepton sectors. Many of these BSM extensions predict new particles or interactions directly accessible at the LHC. This talk will summarize the results of recent searches based on the the full Run 2 data collected by the ATLAS detector at the LHC with a centre-of-mass energy of 13 TeV. These include searches for strong and electroweak production of supersymmetric particles, vector-like fermions, as well as leptoquarks.

Speakers: ATLAS Collaboration, William James Fawcett (University of Cambridge (GB))

proceedings.pdf

wfawcett_atlas_new_phenomena.pdf

09:00 → 11:30 WG4: QCD with Heavy Flavours and Hadronic Final States: Quarkonia from light systems onwards

Conveners: Maria Vittoria Garzelli, Olga Evdokimov (University of Illinois at Chicago (US)), Xuan Li (Los Alamos National Laboratory)

09:00 Quarkonium at Belle II

The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is an upgrade of the B factory facility at KEK in Tsukuba, Japan. The experiment began operation in 2019 and aims to record a factor of 50 times more data than its predecessor. Belle II is uniquely capable of studying the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First discovered by Belle, these now number in the dozens, and represent the emergence of a new category within quantum chromodynamics. We present recent results in new Belle II data, and the future prospects to explore both exotic and conventional quarkonium physics.

Speaker: Klemens Lautenbach (CPPM)

DIS22_quarkonium_belle2_lautenbach.pdf

09:20 Two-photon transitions of charmonia on the light front

We investigate the two-photon transitions $H_{c\bar c} \to \gamma^*\gamma$ of the charmonium system in light-front dynamics. The light-front wave functions were obtained from solving the effective Hamiltonian based on light-front holography and one-gluon exchange interaction within the basis light-front quantization approach. We compute the two-photon transition form factors as well as the two-photon decay widths for S- and P-wave charmonia, $\eta_c$ and $\chi_{cJ}$ and their excitations. Without introducing any free parameters, our predictions are in good agreement with the recent experimental measurements by BaBar and Belle, shedding light on the relativistic nature of charmonium.

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Reference: arXiv:2111.14178 [hep-ph]

Speaker: Meijian Li (University of Jyväskylä)

DIS2022_diphoton_Meijian.pdf

09:40 New Measurements of Quarkonium Production at RHIC with the STAR Experiment

Quarkonium production is modified in ultra-relativistic heavy-ion collisions with respect to p+p collisions due to color-screening and recombination of heavy quark pairs inside the hot QCD medium, known as the quark-gluon plasma (QGP). Such modifications, referred to as hot nuclear matter effects, depend on the size and temperature of the QGP, the binding energy and formation time of the quarknoium, as well as the abundance of heavy quarks created in the collisions. On the other hand, cold nuclear matter effects, such as modification of parton distribution functions in nuclei, energy loss in the cold nuclear matter, nuclear absorption, and co-mover effects, can also induce differences to the p+p reference. Measurements of quarkonium production in different collision systems can disentangle cold and hot nuclear matter effects, and help us better understand the color-screening effect in QGP and extract its properties.

In this talk, we will present new measurements of $J/\psi$ and $\Upsilon$ production with the STAR experiment, including precise results on the nuclear modification factor R$_{pA}$ in p+Au collisions and the first results on R$_{AA}$ in $^{96}_{44}$Ru+$^{96}_{44}$Ru and $^{96}_{40}$Zr+$^{96}_{40}$Zr collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV. Comparisons will be made to results from Au+Au collisions and to model calculations, and physics implications will be discussed.

Speaker: Zhenyu Ye (University of Illinois at Chicago (US))

yezhenyu_DIS2022_Quarkonia_v4.pdf

10:00 Study of $J/\psi$ production vs event multiplicity in $p+p$ and $p+Au$ collisions in the PHENIX experiment at RHIC

$J/\psi$ production has been studied extensively in high energy $p+p$ and heavy ion collisions at RHIC and other facilities in the world, and several promising pQCD based production models have been investigated in details, however, our understanding of the production mechanisms still remain largely uncertain. The recent observations of enhanced particle yields, including $J/\psi$, in high event multiplicity $p+p$ collisions at LHC and RHIC suggest strong contributions from possible semi-hard Multi-Parton Interactions (MPI). Such effect will affect not only our understanding of particle productions in the traditionally considered pQCD “hard-scattering” regime, but also the interpretation of other important global observables, such as event centrality and impact parameter in heavy ion collisions, as well as some spin asymmetries in polarized $p + p(A)$ interactions. To gain further insight into particle production mechanisms in hadronic interactions, we study the $J/\psi$ yield as a function of event multiplicity determined over a broad range of rapidity, considering both possible global and local correlations.

The PHENIX experiment has collected a large sample of $J/\psi \rightarrow \mu^+\mu^-$ decays at the forward (and backward) rapidity of 1.2$<|\eta|<$2.2 in $p+p$ and $p+Au$ collisions at $\sqrt{s_{NN}}$=200 GeV. A comparation of $J/\psi$ yields from $p+p$ and $p+Au$ in the same event multiplicity could shed new light on our understanding of MPI in $p+p$ and also the multi-nucleon interactions in heavy ion $p+Au$ collisions. The latest status of this study will be presented.

Speaker: Dr Ming Xiong Liu (Los Alamos National Laboratory)

PHENIX-JPsi-multiplicity-DIS-052022-final.pdf

10:20 Quarkonium production as a function of charged-particle multiplicity in pp and p--Pb collisions with ALICE at the LHC

Heavy flavour production measurements in hadron collisions serve as testing ground of perturbative QCD (pQCD) calculations. Quarkonia, bound states of heavy quark-antiquark pairs, are unique tools to test both perturbative and non-perturbative aspects of QCD. In particular, the heavy-quark pair production process is described by pQCD while the formation of the bound state is non-perturbative.
In addition, heavy flavour production at the LHC energies is affected by multiparton interactions (MPI). Such events, where several interactions at the parton level occur in a single collision, also need to be taken into account in the models.
Four decades after the discovery of the ${\rm J/}\psi$, the main mechanism behind quarkonia production is still unclear. Other observables, going beyond cross section or polarization measurements, such as the associated production of quarkonia, double J/$\psi$ production, or quarkonium production as a function of charged-particle multiplicity, are expected to provide additional constraints on the theoretical calculations.

In this contribution, associated quarkonium production measurements with ALICE at the LHC are presented. Final results on the production of J/$\psi$, $\psi(2S)$ and $\Upsilon({\it nS})$ as a function of charged-particle multiplicity at forward rapidity in pp collisions at $\sqrt{s}$ = 13 TeV and p--Pb collisions at $\sqrt{s}$ = 5.02 and 8.16 TeV are discussed. They are compared to similar published ALICE measurements of J/$\psi$ production at midrapidity in pp collisions at $\sqrt{s}$ = 13 TeV, as well as with model calculations.
The status of the measurement of the non-prompt J/$\psi$ fraction at midrapidity as a function of charged-particle multiplicity is also shown. Preliminary results for the double J/$\psi$ production cross section in pp collisions at $\sqrt{s}$ =13 TeV are also presented.

Speaker: Theraa Tork (Université Paris-Saclay (FR))

TheraaTORK_DIS.pdf

TORK_DIS_Proceeding.pdf

10:40 Quarkonia Production in Ultraperipheral PbPb collisions at LHCb

Measurements of quarkonia production in peripheral and ultra-peripheral heavy-ion collisions are sensitive to photon-photon and photon-nucleus interactions, the partonic structure of nuclei, and to the mechanisms of vector-meson production. LHCb has studied both coherent and incoherent production of $J/\psi$ mesons in peripheral and ultra-peripheral collisions using PbPb data at forward rapidity with the highest precision currently accessible. Here we will present these measurements, along with comparisons with the latest theoretical models and with results from other experiments. Future UPC measurements with the upgraded LHCb detector in Run 3 will also be discussed.

Speaker: Xiaolin Wang (South China Normal University (CN))

DIS_2018UPC_final.pdf

DIS_proceeding.pdf

11:00 Coffee-break

09:00 → 19:10 WG6: Future Experiments: Session 2

Conveners: Alessandro Polini (Universita e INFN, Bologna (IT)), Michela Chiosso (University of Torino and INFN), Yulia Furletova

09:00 Study of exotic nuclei made easy – a potentially novel topic for physics at the EIC

Low-energy nuclear structure physics continues to be a vibrant field of research, as ever more capable rare isotope facilities look for new elements further away from stability. At these dedicated facilities, short-lived nuclei decay in flight between the production and detection points, making those with shorter decay times difficult to study. The future EIC, however, will have heavy ion beams with energies of 100 GeV/nucleon, leading to a large time dilation effect for produced exotic nuclear fragments resulting in enhanced survival probability. Further, as many of the de-excitation photons will be Lorentz upshifted to energies much larger than background photons present in the detector area, these photons can be used more easily to study the level-structure of the produced exotic nuclei. We present simulation studies of the production and detection of nuclear isotopes at the EIC in electron-heavy nucleus collisions. These studies make use of the BeAGLE generator to model the production of the intermediate, excited nucleus, followed by the de-excitation codes FLUKA and ABLA07. Simulation studies help guide constraints on the far forward detector placement.

Speaker: Brynna Moran (Stony Brook University)

Production and Detection of Exotic Nuclei in the EIC.pdf

09:20 The impact of energy frontier DIS measurements on future hadron collider physics (HL-LHC and FCC-hh)

In this talk we discuss the impact of the physics programme at the LHeC and FCC-he on the respective $hh$ ones, the HL-LHC and the FCC-hh, and the synergies between both collision modes. We address precision SM measurements, Higgs physics, high-mass searches, parton densities, small-$x$ physics and heavy ion physics with $e$A input, extending the discussions in the 2020 LHeC Conceptual Design Report update [1].

[1] P. Agostini et al. (LHeC Study Group), The Large Hadron-Electron Collider at the HL-LHC, J. Phys. G 48 (2021) 11, 110501, e-Print: 2007.14491 [hep-ex].

Speaker: Daniel Britzger (Max-Planck-Institut für Physik München)

220504-britzger-DIS22-LHeCandHLLHC.pdf

09:40 New EW and Higgs Physics with the LHeC and FCC-he

Higgs production cross sections at LHeC (FCC-he) energies are as large (larger than) those at future $Z-H$ $e^+e^-$ colliders. This provides alternative and complementary ways to obtain very precise measurements of the Higgs couplings, primarily from luminous, charged current DIS. Recent results for LHeC and FCC-he are shown and their combination is presented with $pp$ (HL-LHC) cross sections leading to precision comparable to the most promising $e^+e^-$ colliders. We will show the results for the determination of several signal strengths and couplings to quarks, leptons and EW bosons, and discuss the possibilities for measuring the coupling to top quarks and its CP phase, and the search for invisible decays.

Reference: P. Agostini et al. (LHeC Study Group), The Large Hadron-Electron Collider at the HL-LHC, J. Phys. G 48 (2021) 11, 110501, e-Print: 2007.14491 [hep-ex].

Speaker: Christian Schwanenberger (Deutsches Elektronen-Synchrotron (DE))

LHeC_FCCeh_EWK_Higgs.pdf

10:00 Hadron structure at AMBER

AMBER (Apparatus for Meson and Baryon Experimental Research) is a new experiment located on the M2 beam line of CERN SPS. The understanding of the origin of the visible mass in the universe is one of its physics goals. It is known that the Higgs boson mechanism alone is not sufficient to explain the mass of a nucleon. Another phenomenon must interplay with it to explain the emergence of the hadron mass. The AMBER collaboration proposes a broad physics program to address that question under different aspects and learn more about QCD. The experiment is foreseen to run in two phases: with conventional beams delivered by CERN and with an upgraded beamline using radio-frequency cavities to separate the hadron species from the hadron beams. This talk will focus on the Drell-Yan lepton pair, Charmonium and prompt photon production measurements dedicated to the determination of the partonic structure of the pion and the kaon to complement and to compare to the one of the proton in the aim of shedding light onto the emergence of hadron mass mechanism.

Speaker: Carlos Davide Da Rocha Azevedo (University of Aveiro (PT))

CDAzevedoDIS2022.pdf

10:20 Probing nucleon spin structure with inclusive DIS at EIC-ATHENA

Understanding the spin of the proton is one of the fundamental questions in QCD, which is also one of central pillars of the Electron-Ion-Collider (EIC) physics program. The existing data from fixed-target polarized lepton-nucleon DIS experiments and polarized proton-proton experiments, provided us with good knowledge on the quark spin contribution $\Delta \Sigma$ and gluon spin contribution $\Delta G$ in the momentum fraction range $0.005

Speakers: Barak Schmookler (Stony Brook University), Ignacio Borsa Sanjuan (Universidad de Buenos Aires), Paul Richard Newman (University of Birmingham (GB)), Qinghua Xu (Shandong University), Yiyu Zhou (South China Normal University)

DIS22_EICSpin.pdf

10:40 Coherent Deep Virtual Compton Scattering on $^4$He with CORE@EIC

Coherent deep virtual exclusive scattering (DVES) is an important tool for mapping the quark- and gluon-matter densities of nuclei. The separation of quark and gluon contributions can be achieved by combining the $e\,{}^{Z}\!\text{A} \to e\,{}^{Z}\!\text{A}\gamma$ (DVCS), $e\,{}^{Z}\!\text{A}\to e\,{}^{Z}\!\text{A} \phi$ and $e\,{}^{Z}\!\text{A}\to e\,{}^{Z}\!\text{A}J/\Psi$ reactions. This talk will describe the potential of the proposed ``COmpact detectoR for Eic'' (CORE) to achieve precision measurements of coherent DVCS on the $\alpha$-particle at the U.S. Electron Ion Collider (EIC).

Two key challenges for DVES on nuclei are (1) measuring the net invariant momentum transfer squared $t$ to the target ion with sufficient resolution to resolve the diffractive structure; and (2) selecting truly exclusive events without excitation in the final state. Due to the large intrinsic transverse momentum spread of nuclear beams in the EIC, the $t$-resolution in DVES is optimally determined by e.g. $(e,e' J/\Psi\to \mu^+ \mu^-)$ or $(e,e' \phi\to K^+ K^-)$ kinematics. In the DVCS reaction, we must rely upon the EM calorimeter resolution to resolve the $(e,e' \gamma)$ kinematics. With CORE, this is achieved with high resolution PbWO$_4$ calorimetry covering the entire backward (electron going) hemisphere of pseudo-rapidity $-3.5\le \eta \le 0$. Establishing exclusivity is particularly favorable for the $ e \alpha \to e \alpha \gamma$ reaction, as the helium nucleus has no bound excited states. The far-forward trackers ($\eta>4.5$) and zero-degree-calorimeter (ZDC) can tag (and veto) all nuclear break-up channels of the four-nucleon system.

This talk will present the projected $^4$He DVCS yield, and reconstruction resolution with CORE in a variety of EIC kinematics. Extensions to heavier nuclei, will also be discussed.

Speakers: Charles Hyde, Andrey Kim, Carlos MUNOZ CAMACHO

CORE-DVCS-alpha.pdf

11:00 Coffee break

11:30 The STAR Forward Upgrade

The STAR Collaboration has been building a Forward Upgrade to supplement the excellent mid-rapidity capabilities of the STAR Detector for the final years of the RHIC program. The Forward Upgrade utilizes tracking and electromagnetic and hadronic calorimetry to trigger on and measure charged and neutral hadrons, photons, jets, and di-electrons over the pseudorapidity region 2.5 < η < 4. The Forward Upgrade enables critical measurements to test the limits of universality and factorization in QCD when combined with future data from the EIC. In pp collisions, it probes the structure of the nucleon at very high and low x, including for example measurements of the Sivers and Collins effects at x values higher than have been studied in semi-inclusive DIS. In p+Au collisions, it enables to study nuclear modifications of the gluon density at low x and explore non-linear dynamics characteristic of the onset of gluon saturation. In Au+Au collisions, it will probe the longitudinal dynamics of hot QCD matter. This talk will present the status of the Forward Upgrade of operation during the current RHIC Run-2022 and describe the physics program that it will enable.

Speaker: Zhenyu Ye (University of Illinois at Chicago (US))

yezhenyu_DIS2022_ForwardUpgrade_v1.pdf

11:50 Far-Forward Detector Instrumentation for the ATHENA Collaboration at the EIC

Exclusive and diffractive final states will provide a wealth of physics at the future Electron-Ion Collider (EIC). However, measurement of these final states provide a unique challenge for detector design since many of the final-state particles wind up at very large pseudorapidities ($\eta$ > 4.5), which is far beyond the acceptance of the central detector. These so-called “far-forward” particles require detectors to be integrated with the out-going hadron beamline, and therefore require special integration consideration with the accelerator complex. Here, we propose a suite of several detector subsystems which include: 1) a silicon tracking system embedded in the first, large-bore dipole magnet after the central detector, 2) two sets of “potless” Roman pot detectors for tagging protons and other charged particles over a wide range of longitudinal momenta, and 3) a zero-degree calorimeter with a W/SciFi electromagnetic calorimetry system, and a Pb/Sc sampling hadronic calorimeter for reconstructing single neutrons from nuclear breakup, and photons from $\pi^{0}$ decay. Each detector subsystem will be discussed in detail, including considerations for technology and the related impacts with some examples from physics impact studies.

Speaker: Alex Jentsch (Brookhaven National Laboratory, EIC, STAR)

DIS_2022_FF_Detectors_AlexJentsch_v3.pdf

12:10 A Forward Calorimeter in ALICE

FoCAL is a high-granularity forward calorimeter to be installed as an ALICE upgrade subsystem during the LHC Long Shutdown 3 and take data during the LHC Run 4. It consists of a compact silicon-tungsten sampling electromagnetic calorimeter (FoCAL-E) with pad and pixel readout layers to achieve high spatial resolution
for discriminating between isolated photons and decay photon pairs, and a hadron calorimeter based on copper capillary tubes read out using scintillator fibers (FoCAL-H) to improve the isolation energy measurement for prompt photons.

The FoCAL detector extends the ALICE physics programme with the capability, unique at the LHC, to investigate gluon Parton Distribution Functions (PDFs) down to Bjorken-x of ~10^-6 at a momentum transfer Q ~ 4GeV/c, where these are expected to behave non-linearly due to the high gluon densities, with direct photon measurements. Additionally, FoCAL allows forward jet measurements in pp and p-Pb collisions, including gamma-jet and jet-jet correlations, but also photo-production of vector mesons such as the J/\psi in proton-Pb and Pb-Pb ultra-peripheral collisions.

In this presentation we will discuss projected detector performance studies for the main physics observables and results from the test beam campaigns in 2019 and 2021 at DESY and CERN, respectively.

Speaker: Ionut Cristian Arsene (University of Oslo (NO))

IArsene_DIS22_2022May4_v3.pdf

12:30 Deep-inelastic scattering with TeV neutrinos at the Forward Physics Facility

The Forward Physics Facility (FPF) is a proposal to create a cavern with the space and infrastructure to support a suite of far-forward experiments at the HL-LHC. The FPF would make possible a wide range of QCD studies, from proton structure at extremely low-x values to testing BFKL dynamics and modelling hadron and charm production as required by high-energy astrophysics experiments. Furthermore, the FPF would be effectively a neutrino DIS experiment on a nuclear target with a variable bandwidth beam including neutrinos of energies in the TeV range, hence providing a novel handle on quark flavour separation in nucleons and nuclei complementary to that provided e.g. by the Electron Ion Collider. In this talk we summarise the very rich program of QCD and proton/nuclear structure studies that would become available with the realisation of the FPF.

Speaker: Juan Rojo (VU Amsterdam and Nikhef)

rojo-FPF-DIS2022.pdf

12:50 Overview of ATLAS forward proton detectors for LHC Run 3 and plans for the HL-LHC

We describe the status of the ATLAS Forward Proton Detectors (AFP and ALFA) for LHC Run 3 after all refurbishments and improvements done during Long Shutdown 2. Based on analysis of Run 2 data, the expected performance of the Tracking and Time-of-Flight Detectors, the electronics, the trigger, and the readout and detector control and data quality monitoring are described. Finally, the physics interest and the most recent studies of beam optics and detector options for participation at the HL-LHC are discussed.

Speaker: Pragati Patel (Polish Academy of Sciences (PL))

DIS_2022_P_Pragati.pdf

DIS_2022_proc_P_Patel.pdf

13:10 Lunch

15:00 Detector design for a multi-TeV muon collider

The design of a feasible multi-TeV Muon Collider facility is the mandate of the International Design Study collaboration based at CERN and is considered with great interest along the presently on-going US SnowMass process. The physics potential of such a novel future collider is overwhelming, ranging from discovery searches to precision measurements in a single experiment. Despite the machine-design challenges it is possible to reach the uncharted territory of 10 TeV center-of-mass energy or higher while delivering luminosity up to a few 10^35 cm^-2 s ^-1.
The experiment design, the detector technology choices along with the reconstruction tools are strongly affected by the presence of the Beam Induced Background (BIB) due to muon beams decay products interacting at the Machine Detector Interface (MDI).
Full simulation studies at 𝒔 = 1.5 and 3 TeV, adopting the CLIC experiment technologies with important tracker modification to cope with BIB, are the starting point to optimize the detector design and proposing future dedicated R&Ds. Present results and future steps will be discussed.

Speaker: Nazar Bartosik

2022_05_04_bartosik_v1.pdf

15:20 The ATLAS Experiment Upgrade Program

After 9 years of successful operation in proton-proton collisions reaching up to $\sqrt{s}$ = 13 TeV, the ATLAS detector started in 2018 the preparations for an ambitious physics project, aiming the exploration of very rare processes and extreme phase spaces, an endeavor that will require a substantial increase in the integrated luminosity. To accomplish this purpose, a comprehensive upgrade of the detector and associated systems was devised and planned to be carried out in two phases. The Phase-I upgrade foresees new features for the muon detector, for the EM calorimeter trigger system and for all trigger and data acquisition chain. For the Phase-II upgrade, ATLAS will fully replace its inner tracker, install a new timing detector and the calorimeters and muon systems will operate on a free-running readout scheme. This presentation will summarize the physics motivations, the expected performance of the aforementioned projects, as well as the new insights gained during the construction phase.

Speaker: Riccardo Vari (Sapienza Universita e INFN, Roma I (IT))

ATLAS upgrade - DIS2022.pdf

15:40 Precision measurements of (anti)neutrinos interactions with the SAND detector at the DUNE near site

DUNE is a next-generation long baseline experiment for neutrino science. An advanced Near Detector (ND) complex is foreseen for limiting the systematic uncertainties and ensure high precision measurements of neutrino oscillation parameters.

The SAND apparatus is one component of the ND permanently located on-axis with the primary goal of monitoring the beam and measure the neutrino flux. In addition, the accurate control of the configuration, chemical composition and mass of the (anti)neutrino targets in SAND allows precise measurements of high statistics samples of (anti)neutrino interactions in hydrogen and other nuclear targets, including argon.

In this talk the SAND design and its physics program are discussed.

Speaker: Gabriele Sirri (Universita e INFN, Bologna (IT))

gsirri_dis2022_final.pdf

16:00 ATLAS LAr Calorimeter Commissioning for LHC Run-3

The Liquid Argon Calorimeters are employed by ATLAS for all electromagnetic calorimetry in the pseudo-rapidity region |η| < 3.2, and for hadronic and forward calorimetry in the region from |η| = 1.5 to |η| = 4.9. It also provides inputs to the first level of the ATLAS trigger. After successful period of data taking during the LHC Run-2 between 2015 and 2018 the ATLAS detector entered into a long period of shutdown. In 2022 the LHC should restart and the Run-3 period should see an increase of luminosity and pile-up of up to 80 interactions per bunch crossing.

To cope with these harsher conditions, a new trigger readout path have been installed during the long shutdown. This new path should improve significantly the triggering performance on electromagnetic objects. This is achieved by increasing by a factor of ten the number of available units of readout at the trigger level.

The installation of this new trigger readout chain required the update of the legacy system to cope with the new components. It is more than 1500 boards of the precision readout that have been extracted from the ATLAS pit, refurbished and re-installed. The legacy analogue trigger readout that will remain during the LHC Run-3 as a backup of the new digital trigger system has also been updated.

For the new system it is 124 new on-detector boards that have been added. Those boards are able to digitize the calorimeter signal for every collision, i.e. at 40MHz, in a radiative environment. The digital signal is then processed online to provide the measured energy value for each unit of readout and for each bunch crossing. In total this is up to 31Tbps that are analyzed by the processing system and more than 62Tbps that are generated for downstream reconstruction. To minimize the triggering latency the processing system had to be installed underground. There the limited space available imposes the need of a very compact hardware structure. To achieve a compact system, large FPGAs with high throughput have been mounted on ATCA mezzanines cards. In total 3 ATCA shelves are used to process the signal of approximately 34k channels. Given that modern technologies have been used compared to the previous system, all the monitoring and control infrastructure had to be adapted and commissioned as well.

This contribution should present the challenges of such installation, what have been achieved so far and what are the milestones still to be done toward the full operation of both the legacy and the new readout paths for the LHC Run-3. It will also include the first results of the calibration and operation of the new system.

Speaker: Sumit Keshri (Université Paris-Saclay (FR))

DIS2022_Sumit.pdf

16:20 Incorporating Critical Beam Effects into Physics and Detector Simulations for the Electron-Ion Collider

The proposed Electron-Ion Collider (EIC), to be built at Brookhaven National Laboratory, will enable an unparalleled exploration of how the observed properties of nucleons and nuclei emerge from the interactions of their constituent partons. This program will be made possible both by a state-of-the-art machine, capable of colliding polarized electrons with either polarized protons or unpolarized heavy ions with high luminosity and the highly optimized integration of the detector and interaction region with the rest of the collider. One of the key design features of the EIC is the presence of a crossing angle between the colliding beams that reduces the prevalence of parasitic collisions, allowing for the small bunch spacing needed for high luminosity. This crossing angle, either 25 or 35 milliradians depending on interaction region, and other beam conditions such as angular divergence will affect how the beams are oriented in relation to the detector as well as the distribution of particles arising from collisions. It will therefore be essential to include these effects in event simulations for physics and detector studies at the EIC. This contribution will outline two methods for including the crossing angle and other relevant beam effects in simulation: a generator independent afterburner and a scheme based on the internal functionality of the Pythia-8 Monte Carlo event generator. The impact of all beam effects on final state particle distributions will be discussed and procedures to correct for these distortions when performing analyses will be presented.

Speaker: Brian Page (Brookhaven National Laboratory)

dis2022_page_v1.pdf

16:40 Coffee break

17:10 ATHENA – A new detector proposed at the Electron-Ion Collider

The ATHENA (A Totally Hermetic Electron-Nucleus Apparatus) detector is designed to deliver the full physics program of the Electron-Ion Collider (EIC) as set out in the community EIC White Paper and the U.S. National Academy of Sciences report, providing the best possible acceptance, resolution, and particle identification capabilities. ATHENA has been designed to accommodate all necessary subsystems without compromising performance, leaving room for future upgrades as an entirely new detector. Central to the proposal is a new, large-bore magnet with a maximum field strength of 3T. Particle tracking and vertex reconstruction will be performed using next-generation silicon pixel sensors and state-of-the-art micro-pattern gas detectors. Combining magnetic field strength and high resolution and low mass tracking technologies optimizes momentum resolution and vertex reconstruction. The large bore of the magnet allows for layered, complementary, state-of-the-art particle identification technologies. A novel hybrid imaging/sampling electromagnetic calorimeter is proposed for the barrel region of the detector, along with a high-resolution crystal calorimeter in the electron-going direction. The hadron endcap will have calorimetry, tracking, and particle identification detectors optimized for high-momentum hadron identification and high-energy jet reconstruction. We have striven for hermeticity by closely integrating the far-forward and far-backward detectors with the central detector to achieve maximal kinematic coverage and optimize particle detection at small scattering angles. A careful balance between the choice of cutting-edge and mature detector technologies achieves the necessary detector performance while minimizing risk and providing a cost-effective solution achievable on the required timescale. Scalable modern technology choices assure optimum performance for multi-year operations from day one.
The review of the ATHENA detector following the Call for Collaboration Proposals for Detectors at the EIC is still ongoing. The outcome of this review process is expected to be announced at the beginning of March 2022.

Speakers: Bernd Surrow (Temple University), Silvia Dalla Torre (Universita e INFN Trieste (IT))

ATHENA_BerndSurrow_DIS2022.pdf

17:30 An Overview of the Electron-ion collider in China

In this talk, an overview of the physics program, the detector conceptual design, and the project status will be presented. The Electron-Ion Collider in China (EicC) is a proposed high energy nuclear physics facility to be constructed based on the High Intensity heavy-ion Accelerator Facility (HIAF) in Huizhou, China. EicC will be able to place highly polarized ($\sim$80%) electrons in collisions with different ions from polarized ($\sim$70%) protons and helium-3 to unpolarized heavier nuclei up to uranium with viable center of mass energies from 10 to 20 GeV and with the luminosity of (2-4) $\times$ $10^{33}$ cm$^{-2}$s$^{-1}$. This versatility makes EicC an ideal machine to explore the 3D structure of proton in the sea quark region, the partonic structure of nuclei and the parton interaction with the nuclear environment, the exotic states, and origin of mass. In order to perform above precision measurements, a hermetical detector system will be constructed with the cutting-edge technology.

Speaker: Jinlong Zhang (Shandong University)

EICC_DIS2022.pdf

17:50 3D Nucleon Structure with SoLID

For the SoLID Collaboration

SoLID (Solenoidal Large Intensity Device) is a large acceptance, high luminosity device proposed for fully exploiting the potential of the Jefferson Lab (JLab) 12 GeV energy upgrade. The scientific program of SoLID includes one parity-violating deep inelastic scattering (PVDIS) experiment, three semi-inclusive deep inelastic scattering experiments, and one J/$\psi$ production experiment, with several run group experiments. One of the major tasks of SoLID is to deepen our knowledge about the internal structure of the nucleon, which, in terms of its partonic constituents, can be described by a five-dimensional quantum phase-space distribution, the so-called Wigner distribution. Integrating the Wigner distribution over its intrinsic transverse coordinates leads to the transverse-momentum-dependent (TMD) parton distribution function. TMD depicts a three-dimensional imaging of the nucleon and plays an important role in understanding the origin of its spin. This three-dimensional distribution is experimentally accessible via the Drell-Yan process and Semi-Inclusive Deep Inelastic (SIDIS) process. In this talk, an overview of the SoLID program and projections of the 3D imaging of the nucleon will be presented.

This work is supported in part by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.

Speaker: Dr Chao Peng (Argonne National Laboratory)

Nucleon_Structure_with_SoLID.pdf

18:10 Measurement of Lepton-Charge Asymmetry Using a Positron Beam at Jefferson Lab

In testing the Standard Model or searching for beyond-the-Standard Model (BSM) physics, many experiments focus on the measurement of the weak mixing angle. The weak mixing angle is the parameter that unifies the electromagnetic and weak interactions, but only in the SM framework. To investigate the limit of the SM, it is thus important to measure all neutral current couplings, such as electron-electron AV couplings through Moller scattering, electron-quark AV couplings through elastic parity-violating electron scattering, and electron-quark VA couplings though parity-violating deep inelastic scattering. If one can compare the scattering cross section difference between electron and positron deep inelastic scattering, it is also possible to measure the so-called lepton-charge (LC) asymmetry that is directly proportional to the electron-quark AA couplings, the C3q. In this talk I will present the formalism of DIS PV and LC asymmetries, their present measurement status, the possibility of A_LC measurements should a positron beam becomes available at JLab using the planned SoLID spectrometer, along with difficulties of such measurements from both experimental and theoretical aspects.

Speaker: Xiaochao Zheng

talk_DIS2022_C3q_May2022.pdf

18:30 CLAS2 luminosity upgrade and future physics opportunities

Hall-B at Jefferson Lab houses the CEBAF Large Acceptance Spectrometer (CLAS12), designed to carry out high energy electron scattering experiments on various nuclear targets with operating luminosity of up to $L=10^{35}$ cm${-2}$ sec$^{-1}$. CLAS12 was commissioned in early 2018 and started executing the physics program that covers a broad range of topics in nuclear physics. The central focus is the three-dimensional imaging of the quark structure of the nucleon and nuclei. After four years of data taking, new experimental demands require improvement of the operational characteristics of the detector. In particular, efficient reconstruction of multiparticle final states at higher than designed operating luminosity.

A two-stage upgrade is planned for CLAS12 to meet the growing demands for running at higher luminosities with high efficiency of particle reconstruction. The near-term goal is to achieve a luminosity of $L=2\times 10^{35}$ cm${-2}$ sec$^{-1}$ with an improved tracking system. The long-term goal is to reach operational luminosities of $L>10^{37}$ cm${-2}$ sec$^{-1}$ for some selected physics topics. In this talk, we discuss the current performance of the CLAS12 detector, details of planned upgrades to higher luminosities, and the new physics opportunities that these upgrades will provide.

Speaker: Stepan Stepanyan

Stepanyan_CLAS12_DIS22.pdf

18:50 Reconstructing DIS Kinematics at the EIC Using Deep Learning

In a recent paper, we have studied the use of deep learning techniques to reconstruct the kinematics of DIS. In particular, we have used simulated data from the ZEUS experiment at the HERA accelerator facility, and trained deep neural networks to reconstruct the kinematic variables $Q^2$ and $x$. Our approach is based on the information used in the classical construction methods, the measurements of the scattered lepton, and the hadronic final state in the detector, but is enhanced through correlations and patterns revealed with the simulated data sets. Our studies suggest that deep learning techniques to reconstruct DIS kinematics can serve as a rigorous method to combine and outperform the classical reconstruction methods. In our presentation, we will discuss how our technique can be used for physics and detector studies for the upcoming Electron-Ion Collider. We will show results from detailed full detector simulations of the EIC Comprehensive Chromodynamics Experiment (ECCE), a proposal for an EIC detector that is based on a 1.5T solenoid.

Speaker: ABDULLAH FARHAT

farhat_dis2022.pdf

09:20 → 19:35 WG1: Structure Functions and Parton Densities: Session 2

Conveners: Barak Schmookler (Stony Brook University), Klaus Rabbertz (KIT - Karlsruhe Institute of Technology (DE)), Thomas Cridge (University College London)

09:20 Report on the progress of TMD calculation of the proton system and heavy baryons within the BLFQ framework

Transverse-momentum-dependent parton distribution functions (TMD PDFs) are essential for describing elementary high-energy processes involving the hadron, such as semi-inclusive deep-inelastic scattering (SIDIS). Basis Light-Front Quantization (BLFQ) now provides the hadron's light-front wave functions in the leading Fock sector of three valence quarks. We report the first calculations within the BLFQ framework of the leading twist TMDs with a trivial gauge link for proton, Lambda hadron and Lambda c. We discuss the resulting TMDs and compute spin asymmetry using those TMDs. We also investigate the validities of some TMD-related relations and assumptions using our results.

Speaker: Zhi Hu

2022_5_4-DIS2022.pdf

09:40 PDF bias and flavor dependence in TMD distributions

Transverse momentum dependent (TMD) distributions match collinear parton density functions (PDF) in the limit of small transverse distances, which is accounted for by global extractions of TMD distributions. We study the influence of the PDF choice on the determination of unpolarized TMDPDFs and the description of TMD Drell-Yan-pair and Z-boson production data. We find that PDF essentially biases the extraction of TMDPDF. The bias is alleviated once the PDF uncertainty is taken into account and the non-perturbative TMD profile is flavor-dependent. Both points improve the agreement between theory and experiment, substantially increase the uncertainty in extracted TMD distributions, and should be taken into account in future global analyses.

Speaker: Alexey Vladimirov

PDF-bias-Vladimirov.pdf

10:00 PB TMD fits at NLO with dynamical resolution scale

Parton branching solutions of QCD evolution equations have recently been studied
to construct both collinear and transverse momentum dependent (TMD) Parton
distributions. In this formalism, soft-gluon colour coherence effects are taken into account by
introducing the soft-gluon resolution scale. In this talk, we show results of fits to the high precision deep inelastic scattering (DIS) structure function measurements including for the
first time the effects of dynamical, or branching-scale dependent, resolution scales at
Next-to-Leading-Order (NLO) accuracy in the strong coupling

Speaker: Mrs Safura Sadeghi Barzani (1. Department of Physics, Shahid Beheshti University, Iran 2. Elementary Particle Physics, University of Antwerp, Belgium)

DIS-Proceeding.pdf

DIS-talk-2022-p1.pdf

DIS-talk-2022-p1.pdf

DIS-talk-2022-p1.pptx

10:20 Non-perturbative contributions from PB-TMDs and CS kernel determination

With transverse-momentum-dependent parton densities (TMD) obtained from fits to HERA DIS data using the Parton Branching (PB) method, we determine the non-perturbative Collins-Soper (CS) kernel. The CS kernel describes the rapidity evolution of quark TMD parton distribution functions. We use PB-TMD calculations of the Drell-Yan (DY) transverse momentum spectrum at different DY masses. We show that the obtained CS kernel shows, for the first time, reasonable agreement with lattice QCD determinations in the non-perturbative, large b region. We also show that the the results agree with phenomenological extractions of the kernel in the perturbative, low b region.

Speaker: Armando Bermudez Martinez (CMS-DESY)

DIS2022_04_05_22.pdf

10:40 Towards mini-global parton-branchingTMD fits

In the parton branching (PB) approach, collinear and TMD parton densities have been determined by fits to inclusive deep inelastic scattering (DIS) HERA data. This method allows one to simultaneously take into account soft-gluon emission and the transverse momentum recoils in the parton branchings along the QCD cascade. The latter leads to a natural determination of the TMD PDFs in a proton. A crucial development will be to include data from other measurements in a wider kinematic range in order to constrain the TMD PDFs and gain sensitivity to intrinsic transverse momentum contributions. We present preliminary results at NLO for PB TMD fits using the same HERAI+II inclusive DIS, plus HERA jet data and LHC W/Z and ttbar data. The results are compared to the HERAPDF2.0 predictions and a prospect of including other LHC data sets is discussed.

Speakers: Katarzyna Wichmann (Deutsches Elektronen-Synchrotron (DE)), Sara Taheri Monfared (Deutsches Elektronen-Synchrotron (DESY))

kwichmann-dis22-tmd.pdf

11:00 Coffee break

11:30 Probing proton structure at LHCb

With the detector instrumented in the forward region, the collected Z boson events in the LHCb acceptance can be used to probe the proton structure. In this talk, the latest Z boson related measurements will be presented: the Z boson production cross-section measurement at 13 TeV, the Z boson angular coefficients measurement, and the measurement of Z+ c jet events for probing intrinsic charm. The potential contributions of the LHCb data to the global PDF fits will be demonstrated via these analyses, including the sea quark in the larger x region, the transverse momentum dependent (TMD) PDFs, and the intrinsic charm in the proton.

Speaker: Menglin Xu (University of Warwick (GB))

DIS2022_PDFLHCb.pdf

11:50 Determination of proton parton distribution functions using ATLAS data

We present fits to determine parton distribution functions (PDFs) using a diverse set of measurements from the ATLAS experiment at the LHC, including inclusive W and Z boson production, ttbar production, W+jets and Z+jets production, inclusive jet production and direct photon production. These ATLAS measurements are used in combination with deep-inelastic scattering data from HERA. Particular attention is paid to the correlation of systematic uncertainties within and between the various ATLAS data sets and to the impact of model, theoretical and parameterisation uncertainties.

Speaker: Francesco Giuli (CERN)

ATL-COM-PHYS-2022-229.pdf

FGIULI_DIS2022_ATLAS.pdf

12:10 New constraints on PDFs, strong coupling, and SMEFT results using CMS jet data

The CMS measurements of double-differential inclusive jet cross sections of and triple-differential top quark-antiquark pair production cross sections at the center of mass energy of 13 TeV are used together with the data of inclusive deep inelastic scattering to extract the parton distribution functions in the proton, the top quark mass and the strong coupling constant. Using standard model predictions, the analysis at NNLO results in the most precise determination of the strong coupling constant at hadron collider. In an alternative analysis, the standard model is extended with effective couplings for 4-quark contact interactions, leading to a first-ever simultaneous extraction of the standard model parameters and the contact interactions' Wilson coefficients using the LHC data.

Speaker: Toni Makela (Deutsches Elektronen-Synchrotron (DE))

DIS2022_New_Constraints_on_PDFs_alphaS_and_SMEFT_results_using_CMS_jet_data.pdf

New_constraints_on_PDFs_strong_coupling_and_SMEFT_results_using_CMS_jet_data.pdf

12:30 Measurement of the 1-jettiness event shape observable in deep-inelastic electron-proton scattering at HERA

A first measurement of the 1-jettiness event shape observable in neutral-current deep-inelastic electron-proton scattering is presented. The 1-jettiness observable $\tau_{1b}$ is defined such that it is equivalent to the thrust observable defined in the Breit frame. The data were taken in the years 2003 to 2007 with the H1 detector at the HERA ep collider at a center-of-mass energy of 319 GeV and correspond to an integrated luminosity of 351.6 pb$^{−1}$. The triple-differential cross sections are presented as a function of the 1-jettiness $\tau_{1b}$, the event virtuality $Q^2$ and the inelasticity $y$ in the kinematic region $Q^2>150$ GeV$^2$. The data have sensitivity to the parton distribution functions of the proton, the strong coupling constant and to resummation and hadronisation effects. The data are compared to selected predictions.

H1prelim-21-032

Speaker: Daniel Britzger (Max-Planck-Institut für Physik München)

220504-britzger-DIS22-H1-1jettiness.pdf

12:50 Preliminary results from neutron-tagged DIS measurements at JLab with CLAS12 and BAND

The EMC effect -- the modification of quarks in bound nucleons -- is a decades-old open question in QCD research, with far-reaching implications for our understanding of the fundamental structure of matter. While inclusive deep inelastic scattering (DIS) measurements have characterized many features of the EMC effect, their insensitivity to the initial state of the struck bound nucleon limits their ability to pinpoint the mechanisms driving quark modification.

Spectator-tagged deep inelastic scattering measurements provide the opportunity to study bound nucleon structure as a function of the struck nucleon's virtuality. The backward angle neutron detector (BAND) was constructed to measure spectator neutrons in deuterium with bound proton deep inelastic scattering. This novel measurement is sensitive to the bound proton's structure within deuterium.

In my talk, I will explore our theoretical efforts to pinpoint underlying modification of quark structure, present the BAND experiment and its preliminary results, and discuss the implications of our measurement.

Speaker: Efrain Segarra (Massachusetts Institute of Technology)

Segarra_Efrain_DIS2022.pdf

13:10 Lunch

15:00 Measurement of charmonium production in p + p and p + d interaction in the Fermilab SeaQuest experiment

SeaQuest has measured dimuon events from the interaction of 120 GeV proton beam on liquid hydrogen and deuterium targets with dimuon mass between 2 and 8 GeV. These dimuon events contain both the Drell-Yan process and the charmonium ($J/\psi$ and $\psi^\prime$) production. Unlike the Drell-Yan process which probes the antiquark distributions in the nucleons, the charmonium production is sensitive to both quark and gluon distributions. SeaQuest has extracted the (p+d)/(p+p) cross section ratios as well as the differential cross sections for charmonium production in the kinematic region of 0.4 < $x_F$ < 0.9. The (p+d)/(p+p) cross section ratios for charmonium production are found to be significantly different from that of the Drell-Yan process. The measured differential cross sections for charmonium production are compared with theoretical model calculations. The beam energy dependence of the charmonium production cross sections will also be presented.

Speaker: Ching Him Leung (University of Illinois at Urbana-Champaign)

DIS2022_chleung_final.pdf

DIS_proceeding_chleung.pdf

15:20 Inclusive Jet Cross Sections in $pp$ Collisions at $\sqrt{s} = 200$ and $510$~GeV

The cross section for inclusive jet production in high-energy $pp$ collisions is well described by pQCD in the collinear factorization framework, which, together with its high rate and clear signal, makes it a key observable to study the proton structure. For $pp$ collisions at RHIC at a center-of-mass energy of $\sqrt{s} = 200~\text{GeV}$, the STAR detector provides jet measurements at $0.07 ≲ x_T \equiv \frac{2p_{\text{T;jet}}}{\sqrt{s}} ≲ 0.5$. An additional measurement at $\sqrt{s} = 510~\text{GeV}$ covers $0.02 ≲ x_T ≲ 0.3$. At these kinematics, the direct scattering on gluons inside the colliding protons contributes at least half of the total jet production cross section. Measurements of the inclusive jet cross section at RHIC, together with the past Deep Inelastic Scattering measurements, can provide improved constraints on the gluon Parton Distribution Function at high $x$.

Compared to the previous measurement from 2006, improvements in the new measurements include: employing the anti-$k_T$ jet algorithm, a full barrel and endcap electromagnetic calorimeter acceptance, unfolding of the detector response, and correcting jet properties for underlying event contributions. This talk will discuss recent analysis updates pertaining the measurement, as well as challenges in its interpretation.

Speaker: Dmitry Kalinkin (Indiana University / BNL)

dis_2022.pdf

15:40 Measurements of $W^+/W^-$ cross-section ratio in $pp$ collisions at STAR

While the unpolarized valence quark ($d$ and $u$) distributions are well determined from DIS experiments, their sea quark counterparts, $\bar{d}$ and $\bar{u}$, are much less constrained, in particular, near the valence region.
Measurements of $W^+/W^-$ production ratio in $pp$ collider experiments, such as the STAR experiment at RHIC, are sensitive to the $\bar{d}/\bar{u}$ ratio at leading order at a large $Q^2$ set by the $W$ mass.
Presented in this talk are the latest preliminary results and analysis updates of $W^+$ and $W^-$ cross-section ratio measurements via lepton-decay tagging, using the STAR $pp$ collision data at a center-of-mass energy of $\sqrt{s} = 510\,\mathrm{GeV}$ collected in 2017, corresponding to an integrated luminosity of $350\,\mathrm{pb^{-1}}$.
The measurements cover the mid $(|\eta|<1)$ and intermediate rapidities $(1 < \eta < 2)$, probing the $\bar{d}/\bar{u}$ ratio within the proton momentum fraction range of $0.06 < x < 0.4$.

Speaker: Jae Nam (STAR collaboration)

Nam_DIS2022_final.pdf

16:00 Bayesian Monte Carlo extraction of sea asymmetry with SeaQuest and STAR data

We perform a global QCD analysis of unpolarized parton distributions within a Bayesian Monte Carlo framework, including the new $W$-lepton production data from the STAR Collaboration at RHIC and Drell-Yan di-muon data from the SeaQuest experiment at Fermilab. We assess the impact of these two new measurements on the light antiquark sea in the proton, and the $\bar{d}-\bar{u}$ asymmetry in particular. The SeaQuest data are found to significantly reduce the uncertainty on the $\bar{d}/\bar{u}$ ratio at large parton momentum fractions $x$, strongly favoring an enhanced $\bar d$ sea up to $x \approx 0.4$, in general agreement with nonperturbative calculations based on chiral symmetry breaking in QCD.

Speaker: Christopher Cocuzza (Temple University)

DIS2022.pdf

16:20 FORWARD MODELING FOR PARTON DENSITY EXTRACTION

We present a new approach to fitting the $e^+P$ and $e^-P$ high-$x$ data from the ZEUS experiment\footnote{H.~Abramowicz et al. (ZEUS Collaboration), Phys. Rev. D
89, 072007 (2014); I.~Abt et al. (ZEUS Collaboration), Phys.Rev.D 101 (2020) 11, 112009 } based on a full forward modeling from the input PDFs to the expected number of events in measurement bins. Systematic uncertainties are implemented in the predictions of the expected numbers of events and Poisson statistics are used to evaluate the likelihood. The probability distributions for the parameters of the PDFs are extracted with a Markov Chain Monte Carlo approach using Bayesian reasoning implemented in the Julia-based BAT.jl package\footnote{O.~Schulz et al., SN Computer Science volume 2, Article number: 210 (2021)}. For the purpose of this analysis, a QCDNUM\footnote{M.~Botje, Comput. Phys. Commun. 182 (2011) 490, arXiv:1005.1481, Erratum arXiv: 1602.08383
(2016)} add-on package was developed to represent parton densities, structure functions or cross-sections as 2-dimensional cubic interpolation splines. Compared to standard numerical integration approaches, a speed-up of the code of more than three orders of magnitude was achieved without relevant loss of accuracy. We present the techniques developed in formulating our new approach and show first test results on simulated data.

Speaker: Allen Caldwell (Max-Planck-Institut fur Physik (DE))

highx-DIS22.pdf

16:40 Coffee break

17:10 Reconstructing the Kinematics of Deep Inelastic Scattering with Deep Learning

We present a novel method to reconstruct the kinematics of neutral-current deep inelastic scattering (DIS) using a deep neural network (DNN). Unlike traditional methods, it exploits the full kinematic information of both the scattered electron and the hadronic-final state, and it accounts for QED radiation by identifying events with radiated photons and event-level momentum imbalance. The method is studied with simulated events at HERA and the future Electron-Ion Collider (EIC). We will show that the DNN method outperforms all the traditional methods over the full phase space, improving resolution and reducing bias. The DNN-based reconstruction has the potential to extend the kinematic reach of future experiments at the EIC, and thus their discovery potential in polarized and nuclear DIS.

Speakers: Ben Nachman (Lawrence Berkeley National Lab. (US)), Daniel Britzger (Max-Planck-Institut für Physik München), Miguel Ignacio Arratia Munoz (Lawrence Berkeley National Lab. (US)), Owen Long (University of California Riverside (US))

220504-britzger-DIS22-DIS-DNN.pdf

17:30 EKO and yadism: new software tools for DGLAP and DIS

We present EKO, a new PDF evolution code, and yadism, a new DIS structure function library. Both programs produce operators which are independent from the boundary condition, can be stored and quickly applied to several PDFs.As a first application we show a determination of intrinsic charm content of the proton. Both codes are fully open source and written in Python, with a modular structure in order to facilitate usage, readability and possible extensions. We provide a set of benchmarks with similar available tools, finding good agreement.

Speaker: Felix Anton Hekhorn

DIS2022.pdf

17:50 Recent QCD results from the xFitter project

In this talk, the xFitter project is presented. xFitter is an open-source package that provides a framework for the determination of the parton distribution and fragmentation functions for many different kinds of analyses in Quantum Chromodynamics (QCD). xFitter version 2.2.0 has recently been released and offers an expanded set of tools and options. xFitter has been used for a number of analyses performed recently. An emphasis is given on the recently published study performed by the xFitter developers’ team of the pion fragmentation functions.

Speaker: Francesco Giuli (CERN)

DIS2022_xFitter_FGiuli.pdf

FGIULI_DIS2022_xFitter.pdf

18:10 NNLO interpolation grids for jet production at the LHC

Fast interpolation-grid frameworks facilitate an efficient and flexible evaluation of higher-order predictions for any choice of parton distribution functions (PDFs) or value of the strong coupling constant $\alpha_s$. They constitute an essential tool for the extraction of PDFs and Standard Model parameters as well as studies of the dependence on the renormalization and factorization scales. The APPLfast project provides a generic interface between the parton-level Monte Carlo generator NNLOJET and both the APPLgrid and the fastNLO libraries for the grid interpolation. The extension of this toolchain for hadron-hadron collider processes at next-to-next-to-leading order (NNLO) in perturbative QCD is presented with an application to jet production at the LHC.

Speaker: Klaus Rabbertz (KIT - Karlsruhe Institute of Technology (DE))

APPLfast-LHC_DIS2022_202205.pdf

18:30 The impact of various NNLO precision calculations of the Drell-Yan production on the proton PDFs in the CTEQ-TEA global analysis

The Drell-Yan lepton pair productions have been measured to an unprecedented precision level at the LHC. In companion, the theoretical calculations should reach the same level. However, a visible discrepancy among different next-to-next-to-leading order (NNLO) calculations has been discovered by both the CTEQ-TEA group and also by S. Alekhin et al. In this study, we carefully examine the difference among different NNLO codes and also compare with the $q_T$ resummation calculation. We explore the impacts of different calculations on the proton PDFs through the CTEQ-TEA global analysis, based on the latest Drell-Yan data from ATLAS, CMS, and LHCb groups.

Speakers: Alim Ablat (Xinjiang University), C.-P. Yuan (Michigan State University), Keping Xie (University of Pittsburgh), Ibrahim Sitiwaldi (Xinjiang University), Sayipjamal Dulat (Xinjiang University)

DIS2022_DY.pdf

18:50 A new generation of simultaneous fits to LHC data using deep learning

We present a new methodology that is able to yield a simultaneous deter- mination of the Parton Distribution Functions (PDFs) of the proton alongside any set of parameters that determine the theory predictions; whether within the Standard Model (SM) or beyond it. The SIMUnet methodology is based on an extension of the NNPDF4.0 neural network architecture, which allows the addition of an extra layer to simultaneously deter- mine PDFs alongside an arbitrary number of such parameters. We illustrate its capabilities by simultaneously fitting PDFs with a subset of Wilson coefficients within the Standard Model Effective Field Theory framework and show how the methodology extends naturally to larger subsets of Wilson coefficients and to other SM precision parameters, such as the strong coupling constant or the heavy quark masses.

Speaker: Maria Ubiali

DIS22_ubiali.pdf

09:20 → 21:00 WG2: Small-x, Diffraction and Vector Mesons: Session 2

Conveners: Daria Sokhan (CEA Saclay / Glasgow U.), Guillaume Beuf, Rafał Staszewski (IFJ PAN Cracow (PL))

09:40 3D Imaging of Nucleons and Nuclei with ECCE at the Future EIC

The upcoming Electron Ion Collider (EIC) at Brookhaven National Lab will provide novel opportunities to study the structure of light nuclei. Exclusive reactions in particular, such as Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP), have clean final states which allow us to effectively extract Generalised Parton Distribution (GPDs). This makes them important topographic tools in understanding the quark-gluon structure of the nucleon and nuclei. We will present the program of exclusive measurements with the proposed EIC Comprehensive Chromodynamics Experiment (ECCE) detector. We will discuss the simulated detector performance for several key processes and show how ECCE will address the different science goals of the future EIC.

Speaker: Gary Penman

gpenman_DIS22.pdf

10:00 Measuring the spatial gluons distribution in nuclei with ATHENA at the EIC

One of the golden measurements at the Electron-Ion Collider (EIC) is to measure the coherent diffractive Vector Meson (VM) production off heavy nucleus. The measurement is expected to be sensitive to the non-linear gluon dynamics - saturation, and most importantly, it also provides the gluon density distribution of the nucleus. While the measurement was established in the EIC White Paper 10 years ago, it is not until recently that the experimental challenges of this measurement were realized. In this talk, I will discuss the key challenges and their solutions of measuring the diffractive VM in electron-gold collisions, including detector resolution and overwhelming physics background. Full simulations based on the ATHENA detector concept at the EIC will be presented.

Speaker: Zhoudunming Tu

2022-05-04-ZT-v2.pdf

10:20 Accessing GPDs through the exclusive photoproduction of a gamma-meson pair

We consider the exclusive photo-production of a gamma-meson pair, working in the QCD factorisation framework. Explicitly, we consider a rho meson and a charged pion in the final state. This process has a significant advantage over meson production, since it allows us to probe chiral-odd GPDs, which are not well-known experimentally. The computation is performed at leading order and leading twist, and we intend to extend this to $\mathcal{O}(\alpha_s)$ soon. We discuss the prospects of measuring them in experiments, and in particular focus JLab and LHC (in UPC) kinematics.

Speaker: Saad NABEEBACCUS (IJCLab)

DIS2022.pdf

DIS2022-proceedings.pdf

10:40 Nuclear Tomography with Polarized Photon-Gluon Collisions

STAR’s recent observations of the Breit-Wheeler process and vacuum birefringence have demonstrated that ultra-peripheral heavy-ion collisions provide an abundant source of linearly polarized photons. We utilize such polarized photons in diffractive photo-nuclear vector meson production ($\rho^0 \rightarrow \pi^+ \pi^-$) to observe a novel quantum interference effect between non-identical particles (i.e. the $\pi^+$ and $\pi^-$ decay daughters). The interference effect is further employed to isolate the Pomeron momentum contribution, thereby providing a pristine measurement of the gluon distribution within large nuclei.

We present STAR measurements from diffractive photo-nuclear interactions in ultra-peripheral Au+Au and p+Au collisions at $\sqrt{s_{NN}} = 200$ GeV and from U+U collisions at $\sqrt{s_{NN}} = 193$ GeV. These measurements are used to measure the strong interaction radius of gold and uranium nuclei at high energy. We will report the first measurement of the neutron skin of uranium measured at high energy. Finally, we will discuss the implications for experiments at the future Electron Ion Collider, where similar diffractive photo-nuclear interactions are an essential component in the planned physics program.

Speaker: Isaac Upsal (Rice University & USTC)

DIS2022_Upsal.pdf

11:00 Coffee break

11:30 Measurement of the cross-section ratio $\sigma_{\psi(2S )}/\sigma_{J/\psi(1S )}$ in exclusive photoproducion at HERA

The exclusive photoproduction reactions $\gamma p \to J/\psi(1S) p$ and $\gamma p \to \psi(2S) p$ have been studied at an $ep$ centre-of-mass energy of 318 GeV with the ZEUS detector at HERA using an integrated luminosity of 373 pb$^{-1}$. The measurement has been made in the kinematic range $30 < W < 180$ GeV, $Q^2 < 1$ GeV$^2$, $|t| < 1$ GeV$^2$, where $W$ is the photon--proton centre-of-mass energy, $Q^2$ is the photon virtuality and $t$ is the squared four-momentum transfer at the proton vertex. The decay channels used were $J/\psi(1S) \to \mu^+ \mu^-$, $\psi(2S) \to \mu^+ \mu^-$ and $\psi(2S) \to J/\psi(1S) \pi^+ \pi^-$ with subsequent decay $J/\psi(1S) \to \mu^+ \mu^-$. The ratio of the production cross sections $R = \sigma_{\psi(2S)} / \sigma_{J/\psi(1S)}$ has been measured as a function of $W$ and $t$ and compared to previous data in photoproduction and deep inelastic scattering and with predictions of QCD-inspired models of exclusive vector-meson production.

Speaker: Grzegorz Grzelak (University of Warsaw)

GG_DIS2022_ver2.pdf

11:50 Measurement of exclusive vector meson photoproduction in pPb and PbPb collisions with the CMS experiment

The exclusive photoproduction of vector mesons provides a unique opportunity to constrain the gluon distribution function within protons and nuclei. Measuring vector mesons of various masses over a wide range of rapidity and as a function of transverse momentum provides important information on the evolution of the gluon distribution within nuclei. A variety of measurements, including the exclusive J/$\psi$, $\rho$, and $\Upsilon$ meson production in pPb (5.02 and 8.16 TeV) and PbPb (5.02 TeV) collisions, will be presented as a function of squared transverse momentum and the photon-proton center of mass energy. Finally, compilations of these data and previous measurements are compared to various theoretical predictions.

Speaker: Marta Ruspa

ruspa_upload.pdf

12:10 Quarkonium and dilepton photoproduction with ALICE

Heavy ions accelerated at ultra-relativistic energies generate a strong electromagnetic field, leading to photon-photon and photonuclear interactions during the collision. The photoproduction of the J/$\psi$ vector meson has been widely studied in ultra-peripheral collisions with an impact parameter larger than twice the ion radius, where hadroproduction is negligible. In the last few years, this study was extended to heavy-ion collisions with nuclear overlap. The large intensity of the electromagnetic field and the unique kinematic features allowed for the observation of coherently photoproduced J/$\psi$ in peripheral and semi-central collisions, despite the growing contribution of the hadroproduction. J/$\psi$ originated through this mechanism are sensitive probes the nuclear gluon distributions at low Bjorken-$x$ values, and their production measurements might be used in the future to probe the fast-expanding quark-gluon plasma that it is formed during the collision.

The ALICE Collaboration measured the coherent J/$\psi$ photoproduction in Pb--Pb collisions with nuclear overlap at a center of mass energy per nucleon of 5.02 TeV, using the full Run 2 data sample. In this contribution we report on the final results at forward rapidity in the dimuon decay channel and the preliminary results at midrapidity in the dielectron decay channel. At forward rapidity the coherent J/$\psi$ cross section is measured in the centrality ranges 30-90% and 10-30%, although with limited statistical significance in the latter. An upper limit is provided in the centrality range 0-10%. The results are compared with a previous measurement at a lower center of mass energy per nucleon of 2.76 TeV. At midrapidity, the transverse momentum differential cross section was measured for the first time in the 50-70% and 70-90% centrality ranges, thanks to the excellent tracking resolution of the ALICE Time Projection Chamber. The comparison with the available model calculations will be presented as well.

Speakers: Diego Stocco (Centre National de la Recherche Scientifique (FR)), Prof. Jesus Guillermo Contreras Nuno (Czech Technical University in Prague (CZ))

stocco_quarkonium_photoproduction_ALICE.pdf

12:30 Exclusive emissions of polarized $\rho$ mesons at the EIC and the proton content at low-$x$

We present a new study on helicity amplitudes and cross sections for the exclusive production of $\rho$ mesons at the EIC in high-energy factorization. In this framework the analytic expression of amplitudes takes the form of a convolution between an off-shell impact factor depicting the $\gamma^* \to \rho$ transition and a nonperturbative density, known as Unintegrated Gluon Distribution (UGD) that encodes information about the proton structure at low-$x$ and evolves according to the BFKL equation. We come out with an evidence that observables sensitive to the polarization of the incoming virtual photon and the one of the emitted meson allow us to discriminate among different UGD models and to gather quantitative information on the proton content at high energies.

Speaker: Dr Francesco Giovanni Celiberto (ECT*/FBK Trento & INFN-TIFPA)

proceeding_Celiberto_DIS_2022_rho_UGD.pdf

talk_DIS_2022_Celiberto_rho_UGD.pdf

12:50 Exclusive J/Psi photoproduction in ultraperipheral Pb+Pb collisions to NLO pQCD

Coherent exclusive $J/\psi$ photoproduction in heavy-ion ultraperipheral collisions (UPCs) at the LHC, Pb+Pb $\rightarrow$ Pb+$J/\psi$+Pb, has traditionally been suggested as an efficient probe of the gluon distributions. We show, by approximating the GPDs involved in this process with collinear PDFs, that this is indeed the case in the leading order pQCD but at NLO the situation changes rather dramatically. We present the first NLO study of this process in heavy-ion collisions [1], building our numerical code on the NLO calculation of Ref. [2]. We quantify the NLO contributions in the cross section, show the interplay between the real and the imaginary parts of the amplitude and inspect the uncertainties due to the scale choice and PDFs. We compare our calculations for the rapidity-differential cross section with ALICE, CMS and LHCb $J/\psi$ data in Pb+Pb UPCs. The scale dependence is significant but we find a scale choice which adequately reproduces the UPC data for both Run 1 and Run 2 LHC data.

[1] K.J. Eskola, C.A. Flett, V. Guzey, T. Loytainen and H. Paukkunen, work in progress.
[2] D.Yu. Ivanov, A. Schafer, L. Szymanowski, G. Krasnikov, Eur. Phys. J. C 34 (2004) 297.

Speaker: Chris Flett

DIS22_talk1_cflett.pdf

flett_DIS22_proc.pdf

13:10 Lunch

15:00 Heavy quarkonium coherent photoproduction on nuclei

The transverse momentum transfer dependence of differential cross sections for coherent photoproduction of heavy quarkonia on nuclei is studied in the framework of the color dipole model.
In our calculations, the higher-twist nuclear shadowing related to the $\bar QQ$ Fock component of the photon includes the correlation between dipole orientation $\vec r$ and impact parameter of a collision $\vec b$.
For higher Fock components of the photon with additional gluons we included the leading twist gluon shadowing, which represents the main nuclear effect.
The lifetime of such multi-gluon components is very short, even at very high energies, and the corresponding contribution to nuclear shadowing is calculated within a rigorous Green function formalism.
Our results are in good agreement with recent ALICE data on charmonium production in ultra-peripheral nuclear collisions at the LHC. We also present predictions for coherent production of $\psi^{\prime}(2S)$, $\Upsilon$ and $\Upsilon^{\prime}(2S)$ quarkonium states adopting different dipole cross section parameterizations that can be verified by ongoing analysis at the LHC.

Speaker: Dr Michal Krelina (Czech Technical University in Prague)

DIS2022-Krelina-v1.pdf

15:20 Exclusive quarkonium production at next-to-leading order in the Color Glass Condensate framework

Exclusive vector meson production is a powerful process to probe the small Bjorken-$x$ structure of protons and nuclei, as such processes are especially sensitive to gluonic structure and also provide access to the spatial distribution of small-$x$ gluons in nuclei. A powerful theoretical framework to study vector meson production at high energy, and to describe the initial condition of heavy ion collisions, is the Color Glass Condensate (CGC) effective field theory. So far, most calculations in the CGC framework have been done at the leading order. Recent theoretical developments on the NLO heavy vector meson wave function [1] and the NLO virtual photon light-front wave function with massive quarks [2,3] have made it possible to go beyond the leading order, allowing us to include the next-to-leading corrections in $\alpha_s$ and calculate exclusive heavy vector meson production at NLO in the dipole picture for the first time.

In this talk, we will present results from our recent work on longitudinal [4] and transverse [5] NLO vector meson production in the nonrelativistic limit. We demonstrate the cancellation of UV and IR divergences in the NLO calculation, which includes taking into account both the Balitsky-Kovchegov equation describing the rapidity evolution of the dipole amplitude and the renormalization of the leading-order vector meson wave function. The next-to-leading order corrections are found to be sizable; however, their numerical effect on vector meson production is compensated by the dipole amplitude, fitted to HERA inclusive cross section data at NLO [6]. Finally, exclusive $J/\psi$ production is calculated numerically and compared to the existing data. We find that both the NLO corrections and the first relativistic corrections, calculated in Ref.[7], are numerically important and result in a good agreement with the data. We demonstrate that it is possible to simultaneously compute consistently both inclusive and exclusive cross sections at NLO accuracy in the CGC framework.

[1] M. Escobedo and T. Lappi, Phys.Rev.D 101 (2020) 3, 034030, arXiv:1911.01136 [hep-ph]
[2] G. Beuf, T. Lappi and R. Paatelainen, Phys. Rev.D 104 (2021) 5, 056032, arXiv:2103.14549 [hep-ph]
[3] G. Beuf, T. Lappi and R. Paatelainen, in preparation
[4] H. Mäntysaari and J. Penttala, Phys. Lett.B 823 (2021), 136723, arXiv:2104.02349 [hep-ph]
[5] H. Mäntysaari and J. Penttala, in preparation
[6] G. Beuf, H. Hänninen, T. Lappi and H. Mäntysaari, Phys. Rev.D 102 (2020), 074028, arXiv:2007.01645 [hep-ph]
[7] T. Lappi, H. Mäntysaari and J. Penttala, Phys.Rev.D 102 (2020) 5, 054020, arXiv:2006.02830 [hep-ph]

Speaker: Jani Penttala (University of Jyväskylä (FI))

Penttala_Jani_DIS_2022.pdf

15:40 Bayesian inference of the fluctuating proton shape

Determining the multi dimensional structure of protons and nuclei at high energy is one central goal of the future Electron-Ion Collider. This fundamental information is a crucial input for models describing the initial state of heavy ion collisions. In particular the event-by-event fluctuating proton geometry should have a strong effect on the flow and multiplicity distribution in high multiplicity proton-proton and proton-nucleus collisions [1], assuming that a strongly interacting medium is formed in these events. Understanding the subnucleon structure to a high degree of precision is thus a prerequisite of determining whether quark gluon plasma is created in small system collisions.

In order to extract the proton shape fluctuations (see [2]) from HERA exclusive vector meson production data in a statistically rigorous manner, we apply Bayesian inference[3]. This approach enables us to extract likelihood distributions for the non-perturbative parameters describing the proton fluctuating profile, including their correlations. The resulting posterior distributions allow for a systematic propagation of uncertainties when simulating for example high-multiplicity proton-proton and proton-nucleus collisions.

We determine how accurately the HERA data can constrain the proton fluctuating shape, and illustrate how the determined parametrizations can be used to propagate uncertainties to modeling of high-multiplicity proton-proton and proton-nucleus collisions.

[1] H. Mäntysaari, B. Schenke, C. Shen, Phys. Lett. B 772 (2017) 681-686, arXiv:1705.03177 [nucl-th]
[2] H. Mäntysaari, B. Schenke, Phys. Rev. Lett. 117 (2016) 052301, arXiv:1603.04349 [hep-ph], H. Mäntysaari, Rep. Prog. Phys. 83 (2020), 082201, arXiv:2001.10705 [hep-ph]
[3] H. Mäntysaari, B. Schenke, C. Shen, W. Zhao, arXiv:2201.01998 [hep-ph]

Speaker: Dr Heikki Mäntysaari (University of Jyväskylä)

dis2022_mantysaari.pdf

16:00 Energy dependence of the proton geometry in exclusive vector meson production

The gluon radius of the proton is expected to increase at small gluon momentum fractions x, an effect which has hitherto not been considered in the dipole model framework. We investigate the energy dependence of exclusive J/ψ, φ, and ρ production by introducing three models for x dependence of the gluon thickness function. We allow the transverse width of the proton to increase as x decreases, using novel parametrisations in the spherical proton and the hotspot model. We compare these with a model in which the number of hotspots increases as x decreases and confront the models with HERA data. The models exhibit clear differences in the slope of the t-spectra as well as in the cross section ratios between coherent and incoherent events. The data shows a preference for models in which the proton’s size increases as x decreases. Time allowing the analysis will be extended to heavy ion geometries in UPC.

Speaker: Tobias Toll

TollDIS22.pdf

16:20 Exclusive photo-production of charmonium as a tool to distinguish linear and non-linear QCD evolution

We investigate photo-production of vector mesons $J/\Psi$ and $\Psi(2s)$ and their potential use for finding evidence for the presence of non-linear QCD evolution at the LHC and future collider projects. Our study is based both on unintegrated gluon densities, subject to BK (non-linear) and NLO BFKL (linear) QCD low x evolution, and the study of dipole models. While the energy dependence of $\Psi(2s)$ and $J/\Psi$ photo-production cross-sections does not allow to distinguish between linear and non-linear QCD evolution, if we account for theoretical uncertainties, we find that the ratio of of $\Psi(2s)$ and $J/\Psi$ photo-production cross-sections remains approximately constant with energy for linear evolution, while it is rising non-linear evolution. We argue that this is observation is due to general features of the vector meson wave function and might therefore serve to observe and characterize the size of non-linear effects.

Speaker: Martin Hentschinski (Universidad de las Americas, Puebla)

dis_2022.pdf

16:40 Coffee break

17:10 Studies of low-$x$ phenomena with the LHCb detector

With a unique geometry covering the forward rapidity region, the LHCb detector provides unprecedented kinematic coverage at low Bjorken-$x$ down to $x \sim 10^{-5}$ or lower. The excellent momentum resolution, vertex reconstruction and particle identification allow precision measurements down to very low hadron transverse momentum. In this contribution we present the latest studies of the relatively unknown low-$x$ region using the LHCb detector, including recent measurements of charged and neutral hadron production, as well as direct photon and hadron correlations in proton-proton and proton-lead collisions. Comparisons to various theoretical model calculations are also discussed.

Speaker: Imanol Corredoira (Universidade de Santiago de Compostela (ES))

icorredo_lowx_DIS22.pdf

17:30 Angular de-correlation of di-jets and di-hadrons at forward rapidity: interplay of color glass condensate and Sudakov resummation

The STAR collaboration has recently reported on the observation of a significant suppression of forward back-to-back hadron pairs produced in p-Au and p-Al collisions compared to p-p collisions [1]. The A-dependence of this suppression follows the expectations of the color glass condensate effective theory of high-energy QCD, thus giving evidence of the manifestation of gluon saturation at colliders. Comparisons of data with the results of our CGC-based calculations [2] have been also presented. However, such comparisons are at best qualitative due to the current lack of an appropriate implementation of the effect of initial- and final-state soft-gluon radiation (Sudakov resummation) in the cross section of forward production.

In this contribution, we extend our previous work [2] to compute the cross section of forward di-hadron and di-jet production in the CGC framework including Sudakov resummation effects with analytically-controlled methods [3]. We discuss the impact of the Sudakov resummation both in low-pt production at RHIC and high-pt production of di-jets, for which forward data is also available at the LHC [4]. We argue that the impact of soft-gluon radiation is in general better understood at high pt, and that its effect is that of pushing the RpA of forward di-jet production towards unity, thus taming the visibility of the suppression induced by gluon saturation. We identify, thus, hadrons in an intermediate pt range (5-10 GeV) as optimal probes where both genuine saturation signals are visible and Sudakov resummation effects are under control. Quantitative calculations based on the acceptance of the future FoCal upgrade of the ALICE detector are presented. We predict, in particular, that RpA for forward di-hadrons will be as low as 0.75 at Δϕ=π due to gluon saturation [5].

[1] STAR Collaboration, https://arxiv.org/pdf/2111.10396.pdf
[2] J. L. Albacete, G. Giacalone, C. Marquet and M. Matas, https://arxiv.org/abs/1805.05711
[3] A. Stasto, S-Y. Wei, B-W. Xiao, and F. Yuan, https://arxiv.org/abs/1805.05712
[4] ATLAS Collaboration, https://arxiv.org/abs/1901.10440
[5] G. Giacalone, C. Marquet, M. Matas, S-Y. Wei, in preparation

Speaker: Cyrille Marquet (CPHT - Ecole Polytechnique)

santiago22.pdf

17:50 Isolated photon-hadron production in high energy pp and pA collisions

The broadening of the away side peak of the photon-hadron cross section has been predicted to be a sensitive probe of non-linear gluon dynamics in high energy pp and especially pA collisions. In this contribution I plan to show explicit results [1] based on our extensive numerical computation of the photon-hadron cross section that has been recently measured by PHENIX [2] at 200 and 510 GeV in mid-rapidity pp and ALICE [3] at 5.02 TeV in mid-rapidity pp and pA collisions. Our goal is a systematic and reliable phenomenological computation that would yield a realistic prediction of the nuclear effect. To that end we are using a leading order CGC formula and incorportate soft gluon resummation in terms of the Sudakov form factor that was found to be important in dihadron correlations [4]. We compute the angular distributions and out-of-plane transverse momentum distribution and find a satisfactory agreement with all the data in [2] and [3] that further underlines the importance of incorporating soft gluon radiations. Using this as a baseline we further make predictions for the nuclear effect in mid-rapidity pA collisions at 200 GeV and 5.02 TeV.

[1] S. Benic, O. Garcia-Montero, A. Perkov, in preparation
[2] PHENIX collaboration, Phys. Rev. D 95 (2017) no. 7, 072002, Phys. Rev. D 98 (2018) no. 7, 072004.
[3] ALICE collaboration, Phys. Rev. C 102 (2020) no. 4, 044908
[4] A. Stasto, S.-Y. Wei, B.-W. Xiao, and F. Yuan, Phys. Lett. B 784 (2018) 301-306

Speaker: Sanjin Benić

benic.pdf

18:10 C-conjugation odd color charge correlations in the light-front wave function of the proton at moderately small $x$

I discuss C-conjugation odd color charge correlations in the
light-front wave function of the proton at moderately small $x$,
and for perturbative momenta.
The proton is approximated by an effective three-quark Fock
state to which we add the one-gluon emission correction in
light-cone perturbation theory.
The observed non-trivial dependence of the correlations on
impact parameter and on the relative momenta of the gluon probes
is related to n-body quantum correlations in the proton.
From the correlator of three color charge operators presented here
one may obtain the C-odd part of the dipole scattering amplitude (hard
Odderon) at $x >\sim 0.01$ to study its evolution to yet smaller x.

Speaker: Adrian Dumitru

rho3-Odderon.pdf

11:30 → 15:00 WG4: QCD with Heavy Flavours and Hadronic Final States: Open heavy flavour (charm and bottom)

Conveners: Maria Vittoria Garzelli, Olga Evdokimov (University of Illinois at Chicago (US)), Xuan Li (Los Alamos National Laboratory)

11:30 Charm production and hadronization in pp and p--Pb collisions at the LHC with ALICE

Studies of open-charm hadron production in a partonic rich environment are performed at the LHC to investigate charm-quark hadronization mechanisms. Recent measurements of different charm meson (${\rm D^0}$, ${\rm D^+}$, ${\rm D^+_{\rm s}}$, ${\rm D^{*+}}$) and baryon ($\Lambda^+_{\rm c}$, $\Xi^{0,+}_{\rm c}$, $\Sigma^{0,++}_{\rm c}$, $\Omega^0_{\rm c}$) production in pp collisions at $\sqrt{s}$ = 5.02 TeV and $\sqrt{s}$ = 13 TeV allowed the measurement of the fragmentation fractions and the charm cross section with unprecedented precision. The measurements show that the fragmentation fractions significantly differ from the ones observed in ${\rm e^+e^-}$ collisions. This contradicts the typical picture of universality of the fragmentation functions across the different collision systems.
Furthermore, the baryon to meson ratios $\Lambda^+_{\rm c}/{\rm D^0}$, measured down to $p_{\rm T}=0$, and $\Xi^{0,+}_{\rm c}/{\rm D^0}$ in p--Pb collisions will be discussed. In p--Pb collisions a modification of the hadronization mechanisms could be present due to cold nuclear matter effects and possible collective phenomena. Several models are able to reproduce the measured baryon to meson ratios. A systematic comparison between data and models will help to understand charm quark hadronization in pp and p--Pb collisions.

Speaker: Annalena Sophie Kalteyer (GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE))

DIS2022.pdf

DIS2022_Proceeding_Charm_ALICE.pdf

11:50 Forward charm production at hadron colliders

We present a phenomenological study for the production of the charm quark
in the forward and far forward region. We discuss theory predictions for differential cross sections at NLO in QCD obtained with the S-ACOT-MPS General Mass Variable Flavor Number (GMVFN) scheme applied to pp collisions.
We show the impact of charm-quark fragmentation contributions on the theory prediction and we discuss applications at future Forward Physics Facilities such as FASERnu. We discuss about the possibility of exploring QCD and extract parton distribution functions (PDFs) in extended kinematic regions of hadronic reactions that are currently not experimentally accessible.

Speakers: Keping Xie (University of Pittsburgh), Marco Guzzi (Kennesaw State University), Pavel Nadolsky (Southern Methodist University)

HF-production-DIS2022.pdf

HF-production-DIS2022.pdf

HF-production-DIS2022.pptx

12:10 Neutrinos from charm in the forward region

The proposed forward physics facility at the LHC will offer the opportunity to collect a large data set of neutrino deep inelastic scattering in the energy range of $\sim 100-1000$ GeV. Already with Run 3, the FASER$\nu$ and SND@LHC experiments will collect neutrino events in the forward region 480 m from the ATLAS interaction point. The high energy electron neutrino and tau neutrino fluxes at these detectors come from hadroproduction of heavy flavor, predominantly charm hadrons. The predicted flux of neutrinos at the forward region is tied to the parton distribution functions, in particular the gluon PDF, in both the small $x$ and large $x$ regimes. We present predictions of the flux of neutrino and antineutrinos from charm for Run 3, where the approved experiments cover pseudorapidities larger than 7.2, and for the HL run for pseudorapidities larger than 6.9. We discuss the uncertainties in the flux that comes from PDF and QCD scale uncertainties in a NLO perturbative QCD evaluation.

Speaker: Mary Hall Reno

DIS-2022-Reno.pdf

12:30 Beauty production in small systems with ALICE at the LHC

Measurements of the production of hadrons containing beauty quarks
in pp and p--Pb collisions provide an important test of quantum chromodynamics calculations as well as the possibility to investigate fragmentation mechanims and modifications of the PDF in nuclei.

The use of machine-learning techniques for multi-class classification, coupled with the excellent particle identification, track and decay-vertex reconstruction capabilities of the ALICE experiment, is exploited to separate the non-prompt and prompt D mesons and $\Lambda_{\rm c}$ baryons, respectively produced in beauty-hadron decays and directly from the charm-quark fragmentation. The same technique also allows for the first time the measurement of the non-prompt ${\rm D}^{*}$ polarization and the analysis of the non-prompt D-meson fractions as a function of multiplicity in pp collisions at $\sqrt{s}=13$ TeV.

The beauty production is also investigated via the measurements of b-tagged jets in pp and p–-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV. The final results will be presented. The nuclear modification factor $R_{\rm pPb}$ is found consistent with unity and the fraction of b-jets among inclusive jets down to $p_{\rm T}=10$ GeV/${\it c}$ is found lower than in previous measurements of b-jets done at the LHC. The measurements of the b$\bar{\rm b}$ production cross section at midrapidity are compared to FONLL predictions and to NNLO calculations.

Speaker: Pietro Antonioli (Universita e INFN, Bologna (IT))

Antonioli-20220504.pdf

12:50 ATLAS results on B_c production and decays

Recent results from the proton-proton collision data taken by the ATLAS experiment on B_c production and decays will be presented. The measurement of the differential ratios of the B_c+ and B+ production cross sections at 8 TeV will be shown. New results on the B_c decays to J/psi Ds(*) final states obtained with the Run 2 data at 13 TeV will also be reported.

Speaker: Sally Seidel (University of New Mexico / ATLAS)

dis2022-talk.pdf

13:10 Lunch

15:00 → 19:10 Joint WG3+WG4 session:: Top-quark physics: new theoretical and experimental results

Conveners: Adam Orion Martin (University of Notre Dame (US)), Heather Gray (UC Berkeley/LBNL), Heidi Angelika Rzehak, Maria Vittoria Garzelli, Olga Evdokimov (University of Illinois at Chicago (US)), Xuan Li (Los Alamos National Laboratory)

15:00 Latest top quark measurements with the CMS detector

The most recent results on top quark physics, obtained using data collected with the CMS experiment at 5.02 and 13 TeV center-of-mass energies, are presented.

Speaker: Hideki Okawa (Fudan University (CN))

okawa_CMSTop_DIS2022.pdf

okawa_DIS2022.pdf

15:20 Top quark precision measurements with the ATLAS experiment

The large top quark samples in top quark pair and single top production have yielded measurements of the production cross section of unprecedented precision and in new kinematic regimes. They have also enabled new measurements of top quark properties that were previously inaccessible. In this contribution the highlights of the ATLAS top quark precision program are presented. ATLAS presents in particular new measurements of the production cross section and production asymmetry of highly boosted top quark pairs and of the top quark polarization in t-channel single top production.

Speaker: Shayma Wahdan (Bergische Universitaet Wuppertal (DE))

Shayma_Wahdan_DIS2022_Santiago_Spain.pdf

15:40 Searches for rare top quark production and decay processes with the ATLAS experiment

Run 2 of the LHC has witnessed the observation of many rare top quark production processes predicted by the Standard Model and has boosted searches for flavour-changing-neutral-current interactions of the top quark, that are heavily suppressed in the SM. In this contribution highlights of searches by the ATLAS experiment for rare processes involving top quarks are shown. Results are presented for several associated top quark production processes of top quarks with Standard Model gauge bosons. The recent observation of associated production of a single top quark with a photon completes the list of processes and adds sensitivity to the EW couplings of the top quark. ATLAS furthermore reports strong evidence for the four-top-production process. Finally, results are presented of searches for flavour-changing-neutral-current processes involving top quarks. Searches in the full run 2 data set have been performed for tqg, tqgamma, tqZ and tqH interactions, with bounds exceeding previous limits by large factors.

Speaker: Marcos Miralles Lopez (IFIC (U.Valencia-CSIC))

TalkMarcosMiralles.pdf

16:00 Evidence for top quark production in nucleus-nucleus collisions with the CMS experiment

Evidence for the production of top quarks in heavy ion collisions is reported in a data sample of lead-lead collisions recorded in 2018 by the CMS experiment at a nucleon-nucleon center-of-mass energy of $\sqrt{s_{_{\mathrm{NN}}}} = 5.02$ TeV, corresponding to an integrated luminosity of $1.7\pm0.1\,\mathrm{nb}^{-1}$. Top quark pair ($\mathrm{t\bar{t}}$) production is measured in events with two opposite-sign high-$p_\mathrm{T}$ isolated leptons ($\ell^\pm\ell^\mp =\,\mathrm{e}^{+} \mathrm{e}^{-},\,\mu^{+} \mu^{-},\,\mathrm{and}\,\mathrm{e}^{\pm} \mu^{\mp}$). We test the sensitivity to the $\mathrm{t\bar{t}}$ signal process by requiring or not the additional presence of b-tagged jets, and hence demonstrate the feasibility to identify top quark decay products irrespective of interacting with the medium (bottom quarks) or not (leptonically decaying W bosons). To that end, the inclusive cross section ($\sigma_\mathrm{t\bar{t}}$) is derived from likelihood fits to a multivariate discriminator, which includes different leptonic kinematic variables with and without the b-tagged jet multiplicity information. The observed (expected) significance of the $\mathrm{t\bar{t}}$ signal against the background-only hypothesis is 4.0 (5.8) and 3.8 (4.8) standard deviations, respectively, for the fits with and without the b-jet multiplicity input. After event reconstruction and background subtraction, the extracted cross sections are $\sigma_\mathrm{t\bar{t}} = 2.03 ^{+0.71}_{-0.64}$ and $2.54 ^{+0.84}_{-0.74}\,\mu\mathrm{b}$, respectively, which are lower than, but still compatible with, the expectations from scaled proton-proton data as well as from perturbative quantum chromodynamics predictions. This measurement constitutes the first crucial step towards using the top quark as a novel tool for probing strongly interacting matter.

Speakers: CMS Collaboration, Luis Alcerro Alcerro (The University of Kansas (US))

DIS2022.pdf

16:20 Non-factorisable QCD corrections to t-channel single-top production at NNLO

Single top quarks are mainly produced through a t-channel W boson exchange, $q + b \to q^\prime + t$, at the LHC. The computation of the last missing ingredient for NNLO QCD corrections, the non-factorisable two-loop amplitude, was recently completed.
Despite being colour-suppressed and hence previously neglected, there is reason to expect this correction to have an impact comparable to that of the factorisable contribution.
In this talk I will present the calculation of the necessary two-loop virtual correction for the non-factorisable contribution and discuss its phenomenological impact on single-top production.

Speaker: Christian Broennum-Hansen

beamer.pdf

16:40 Coffee break

17:10 Higher-order corrections in $tq\gamma$ production

We present calculations of QCD corrections for the associated production of a single top quark and a photon ($tq\gamma$) in proton-proton collisions. We calculate the NLO cross section as well as the approximate NNLO (aNNLO) cross section with soft-gluon corrections, including theoretical uncertainties, at collider energies of up to 100 TeV. We show results with various choices of parton distributions and kinematical cuts, and we also calculate top-quark and photon differential distributions. The theoretical prediction is in excellent agreement with a 13 TeV measurement at the LHC.

Speaker: Prof. Nikolaos Kidonakis

Kidonakis-tqgamma.pdf

17:30 Top-antitop cross sections at high energies

I present theoretical results for top-antitop pair production cross sections at current and future collider energies up to 100 TeV. I discuss the contribution of higher-order terms in the perturbative series. I show the very high quality of the soft gluon approximation through NNLO and the effect of contributions at aN$^3$LO.

Speaker: Nikolaos Kidonakis

Kidonakis-ttbar.pdf

17:50 Projected transverse momentum resummation in the top-antitop pair production at LHC

In this work, the spectra for the observables, $q_{\mathrm{T}}^{\mathrm{out}}=\left| \vec{q}_{t\bar{t}}\cdot \Big(\frac{\vec{p}_{t}}{|\vec{p}_{t}|}\times\vec{n}\Big) \right|$ and $q_{\mathrm{T}}^{\mathrm{in}}=\sqrt{q_{\mathrm{T}}^2-(q_{\mathrm{T}}^{\mathrm{out}})^2}$, are investigated for the process $pp\to t\bar{t}X$. Here $\vec{p}_t$ stands for the spatial momentum of the top quark and $\vec{n}$ represents one of the beam directions. In analogy to the inclusive $q_{\mathrm{T}}$ distribution, the $q_{\mathrm{T}}^{ \mathrm{out}}$ and $q_{\mathrm{T}}^{\mathrm{in}}$ spectra in their respective asymptotic regimes are also governed by the soft and collinear radiations about the beam, which can therefore incite poor convergence in the outcomes from the perturbative calculation. To improve this, we carry out the resummation on those soft/collinear fluctuations with the aid of the SCET-based (rapidity) renormalisation groups. To validate, we compare the outputs from the fixed-order calculation with those from SCET, and observe the agreement in both NLO and N$^2$LO in the limit $q_{\mathrm{T}}^{ \mathrm{out/in}}\to 0$ GeV. As to the resummed distributions, the results up to N$^2$LL precision have been evaluated and in comparison to NLL, the manifest decline in the uncertainty has been found out amongst the N$^2$LL curves.

Speaker: Wanli Ju

Proceedings_DIS2022.pdf

Wanli_Ju_DIS2022.pdf

18:10 Impact of Top-quark pair production on CTEQ PDFs

We discuss the impact of top-quark pair production differential cross section measurements from CMS and ATLAS at center of mass energy of 13 TeV on the CT18 proton PDFs. We discuss various phenomenological aspects of novel QCD analyses obtained with this extended baseline of data sets and in particular the impact on the gluon PDF.

Speakers: Marco Guzzi (Kennesaw State University), Keping Xie (University of Pittsburgh)

DIS2022-talk-mguzzi.pdf

18:30 Heavy-flavor production from QCD evolution in dense matter

Heavy meson production in reactions with nuclei is a new frontier to understand QCD dynamics and hadronization in nuclear matter. Measurements in various colliding systems, including Pb-Pb, Xe-Xe, O-O, p-Pb, and p-O at the LHC and the upcoming sPHENIX experiment, enable precision tests of the medium-size, temperature, and mass dependencies of the in-medium QCD evolution. We employ a coupled DGLAP evolution framework that takes advantage of splitting functions recently obtained in SCET${}_G$ and HTL-motivated collisional energy loss effects. With the jet-medium couplings constrained to the nuclear modification factor of charged hadrons $R_{AA}$ in Pb-Pb collisions at 5.02 TeV, we present predictions for heavy-meson $R_{AA}$ in Xe-Xe, O-O and p-Pb collisions at the LHC. We find suppression that scales non-trivially with the quark mass and medium properties. In particular, there can be sizeable collision-induced attenuation of heavy mesons in small systems such as oxygen-oxygen and high-multiplicity $p$-Pb events. Finally, we analyze the impact of different models of initial-state parton dynamics on the search for QGP signatures in small colliding systems.

Speaker: Weiyao Ke (Los Alamos National Laboratory)

DIS2022-WK-May04.pdf

proceeding.pdf

18:50 Equation of state of quark gluon plasma under the strong magnetic field

Speaker: yogesh kumar

EoSTDMF@yogesh_DIS2022.pdf

20:00 → 22:30 Conference dinner

Thursday 5 May

08:10 → 15:50 WG5: Spin and 3D Structure: Session 3

Conveners: Qinghua Xu (Shandong University), Yoshiyuki Miyachi (Yamagata University (JP)), yoshitaka hatta (BNL)

09:00 Measurement of angular distribution of Drell--Yan dimuons by the SeaQuest experiment at Fermilab

The structure of the proton has been studied by measuring the parton distribution function, which is the parton density distribution as a function of the longitudinal momentum of the parton, for long time. In the last few decades, the three-dimensional imaging of nucleon, such as the transverse momentum dependent parton distribution functions (TMDs), has received attention to better understand the structure of the nucleon. The Boer--Mulders function is one of the TMDs that represents the correlation between the transverse spin and the transverse momentum of the quark. The Boer--Mulders function can be extracted from the azimuthal angular distribution of the Drell--Yan process. In the naive Drell--Yan model, the angular distribution of the Drell--Yan process has a $\cos\theta$ modulation ($\lambda=1$) while no $\cos2\phi$ ($\nu=0$) modulation, where $\theta$ and $\phi$ denote the polar and azimuthal angle, respectively. However, the sizable $\cos2\phi$ modulation has been observed by NA10 and E615 experiments, which are pion-induced Drell--Yan experiments. The E866 experiment reported the first and only results of the angular distribution of the proton-induced Drell--Yan process using 800 GeV proton beam. In contrast to pion-induced Drell--Yan experiments, E866 shows significantly smaller $\cos2\phi$ modulation. The SeaQuest experiment is a Drell--Yan experiment at Fermilab that measured the Drell--Yan dimuons using the 120 GeV proton beam colliding with liquid hydrogen and deuterium targets. We have measured the angular distribution of the proton-induced Drell--Yan dimuons in a kinematics region different of E866. In this talk, the progress of the angular distribution analysis will be presented.

Speaker: Dr Kei Nagai (Los Alamos National Laboratory)

dis2022.pdf

09:20 TMDs, PDFs, and multiparton distributions of spin-1 hadrons and their relations

There are new polarized structure functions, which do not exist for the spin-1/2 nucleons, in a spin-1 hadron such as the deuteron. In the near future, we expect that physics of spin-1 hadrons will become a popular topic, since there are experimental projects to investigate spin structure of the spin-1 deuteron at the Jefferson Laboratory, the Fermilab, the NICA, the LHCspin, and the electron-ion colliders in US and China in 2020's and 2030's.

We explain possible transverse-momentum-dependent parton distribution functions (TMDs) for spin-1 hadrons up to twist 4 by decomposing a quark correlation function with the conditions of the Hermiticity and parity invariance [1]. We found 30 new structure functions in the twist 3 and 4 in our work. In addition, we indicated that new fragmentation functions exist in tensor-polarized spin-1 hadrons. Integrating the TMDs over the transverse momentum, we found new collinear PDFs for spin-1 hadrons. For these PDFs, we showed that a twist-2 relation and a sum rule exist for the tensor-polarized parton distribution functions $f_{1LL}$ and $f_{LT}$ [2]. We also indicated that four twist-3 multiparton distribution functions $F_{LT}$, $G_{LT}$, $H_{LL}^\perp$, and $H_{TT}$ exist for tensor-polarized spin-1 hadrons. Furthermore, we showed relations among the collinear parton- and multiparton-distribution functions for the spin-1 hadrons by using the equation of motion for quarks [3]. Useful relations were obtained (1) for the twist-3 PDF $f_{LT}$, the trasverse-momentum moment PDF $f_{1LT}^{\,(1)}$, and the multiparton distribution functions $F_{G,LT}$ and $G_{G,LT}$; (2) for the twist-3 PDF $e_{LL}$, the twist-2 PDF $f_{1LL}$, and the multiparton distribution function $H_{G,LL}^\perp$. In addition, so called a Lorentz-invariance relation was obtained for $f_{1LT}^{\,(1)}$, $f_{1LL}$, $f_{LT}$, and $F_{G,LT}$. These relations are useful in future experimental investigations on the spin-1 structure functions.

[1] S. Kumano and Qin-Tao Song, Phys. Rev. D 103 (2021) 014025.
[2] S. Kumano and Qin-Tao Song, JHEP 09 (2021) 141.
[3] S. Kumano and Qin-Tao Song, Phys. Lett. B 826 (2022) 136908.

Speaker: Shunzo Kumano (Japan Women's University / KEK)

DIS-2022-05-Kumano.pdf

09:40 The azimuthal asymmetries in \rho^0 production in ultraperipheral heavy ion collisions

A sizable cos 4ϕ azimuthal asymmetry in exclusive dipion production near ρ0 resonance peak in ultraperipheral heavy-ion collisions recently has been reported by STAR collaboration. We show that both elliptic gluon Wigner distribution and final-state soft photon radiation can give rise to this azimuthal asymmetry. The fact that the QED effect alone severely underestimates the observed asymmetry might signal the existence of the nontrivial correlation in quantum phase distribution of gluons.

Speaker: Dr Yajin Zhou

Yajin Zhou DIS2022.pdf

10:00 Jet-axis probe of the TMD PDFs and phenomenology of time-reversal-odd jet function

We re-interpret the jet clustering as an axis-finding procedure which, along with the proton beam, defines the virtual photon transverse momentum $q_T$ in deep inelastic scattering (DIS). In this way, we are able to probe the nucleon intrinsic structures with jets in a fully inclusive manner, similar to the Drell-Yan process. We present the factorization formulae and a complete list of the leading-power azimuthal asymmetries in deep-inelastic scattering of a nucleon. We show that, within the winner-takes-all axis finding algorithm, couplings of the time-reversal-odd jet functions to the quark transversities and the Boer-Mulders functions could give rise to azimuthal asymmetries. We also give predictions for the azimuthal asymmetry of back-to-back dijet production in $e^+e^-$ annihilation.

Speaker: Wai Kin Lai (South China Normal University)

DIS_2022_Proceeding_WKLai.pdf

DIS_2022_WKLai.pdf

10:20 $\cos2\phi$ azimuthal asymmetry in back-to-back $J/\psi$ and jet production at the EIC

We present a calculation of the $\cos2\phi$ azimuthal asymmetry in $e ~p\rightarrow e ~J/\psi ~Jet~ X$, where $J/\psi-Jet$ pair is almost back-to-back in the transverse plane, within the framework of the generalized parton model (GPM) and assuming TMD factorization. This probes the Weisz{\"a}ker-Williams type linearly polarized gluon distribution. We calculate the asymmetry using non-relativistic QCD (NRQCD) for the production of $J/\psi$ incorporating both color singlet and color octet contributions. We study the dependence of the asymmetry on the parameterizations of the gluon TMDs used as well as the impact of TMD evolution on the asymmetry. We present numerical estimates in the kinematical regions to be accessed by the future EIC.

Speaker: Mr Amol Pawar (IIT Bombay)

DIS_2022_presentation.pdf

10:40 Azimuthal Transverse Single-Spin Asymmetries of Inclusive Jets and Identified Hadrons Within Jets in Polarized $pp$ Collisions at $\sqrt{s}$ = 200 GeV

Understanding the origin of transverse single-spin asymmetries is a long-standing challenge in strong interaction physics. Significant progresses have been made in the last few decades from both the experimental and theoretical sides, which fueled the rapid development of twist-3 and transverse-momentum-dependent (TMD) factorization schemes. Measurement of the azimuthal distribution of identified hadrons produced during the fragmentation of a large transverse momentum jet offers a unique opportunity to study the TMD physics in hadronic collisions, such as the Collins effect which involves the correlation of the quark transversity and the Collins fragmentation functions. In 2012 and 2015, STAR collected $\sim$22 $\mathrm{pb^{-1}}$ and $\sim$52 $\mathrm{pb^{-1}}$ of transversely polarized $pp$ data at $\sqrt{s}$ = 200 GeV, respectively. These datasets enable the most precise measurement of the transverse single-spin asymmetries in 200 GeV $pp$ collisions to date. Results of the asymmetries for inclusive jets and identified pions, kaons, and protons in jets using these datasets will be presented.

Speaker: Ting Lin

DIS2022_CollinsAsym_final_20220502.pdf

11:00 Coffee break

11:30 Transverse Single Spin Asymmetry for Inclusive and Diffractive Electromagnetic Jets at Forward Rapidities in p↑+p Collisions at √s = 200 GeV and 510 GeV at STAR

There have been numerous attempts, both theoretical and experimental, to understand the origin of the unexpectedly large transverse single spin asymmetry ($A_{N}$) for the inclusive hadron production at forward rapidities observed in $p^{\uparrow}$+p collisions at various center-of-mass energies. The twist-3 contributions in the collinear factorization framework and the transverse-momentum-dependent contributions from the initial-state quark and gluon Sivers functions and/or final-state Collins fragmentation functions are potential explanations to this puzzle. Previous analyses of $A_{N}$ for forward $\pi^{0}$ and electromagnetic jets in $p^{\uparrow}$+p collisions at STAR indicated that there might be non-trivial contributions to the large $A_{N}$ from diffractive processes [1]. The STAR Forward Meson Spectrometer (FMS) and Endcap ElectroMagnetic Calorimeter (EEMC) can detect photons, neutral pions, and eta mesons in the forward direction, with pseudo-rapidity coverages of $2.6 < \eta < 4.2$ and $1.0 < \eta < 2.0$, respectively. In this talk, we will present the latest preliminary results and analysis updates on $A_{N}$ for inclusive and diffractive electromagnetic jets in the FMS and EEMC using $p^{\uparrow}$+p data at $\sqrt{s} =$ 200 GeV and 510 GeV collected at STAR.

[1] (STAR) J. Adam et al., Phys. Rev. D 103, 092009 (2021)

Speaker: Xilin Liang (University of California, Riverside)

Liang_DIS2022.pdf

Liang_DIS_2022_proceeding.pdf

11:50 Measurement of longitudinal spin transfer of $\Lambda(\bar{\Lambda})$ hyperon in polarized p+p collisions at $\sqrt{s}=200$ GeV at RHIC-STAR

Understanding the origin of the proton spin is one of the most fundamental and challenging questions in QCD. Much progress has been made since the first surprising results %on the spin structure of the proton by the EMC experiment in the late 1980s. However, for the helicity distributions of the proton, contributions from sea quarks, especially from the strange quark (anti-quark), $s(\bar{s})$, are still not well constrained by experimental data. Since the spin of the $\Lambda(\bar{\Lambda})$ hyperon is expected to be carried mostly by its constituent $s(\bar{s})$ quark, measurements of the longitudinal spin transfer, $D_{LL}$, of the $\Lambda(\bar{\Lambda})$ hyperon can thus shed light on the helicity distribution of the $s(\bar{s})$ quark in the proton and the longitudinally polarized fragmentation functions. In particular, measuring $D_{LL}$ as a function of the jet momentum fraction carried by the $\Lambda(\bar{\Lambda})$ hyperon can directly probe the polarized jet fragmentation functions. In this talk, we will present the status of the $D_{LL}$ analysis using data collected at RHIC-STAR in 2015, for the hyperon pseudo-rapidity $|\eta| < 1.2$ and transverse momenta up to $8.0$ $\mathrm{GeV}/c$. This data set corresponds to an integrated luminosity of 52 $\mathrm{pb}^{-1}$ and is about twice as large as the 2009 data used for the previously published $D_{LL}$ results.

Speaker: Mr Yi Yu (Shandong University)

HyperonSpinTransfer_DIS2022.pdf

12:10 Measurement of transverse polarization for Lambda production in pp collisions at STAR

Spontaneous polarization of $\Lambda/\bar{\Lambda}$ has been observed over four decades ago, but still eludes a definitive explanation. One possible origin is the effect arising from polarizing fragmentation functions (PFFs), which describe the production of polarized hadrons from the fragmentation of an unpolarized parton. In 2019, the Belle experiment observed significant transverse polarization of $\Lambda/\bar{\Lambda}$ in unpolarized $e^{+}e^{-}$ annihilations, indicating significant non-zero PFFs. In pp collisions, measurements of transverse polarization of $\Lambda$/$\bar{\Lambda}$ inside a jet could provide important constraints for the PFFs. In 2015, the STAR experiment at RHIC collected a dataset of $pp$ collisions at $\sqrt{s}$ = 200 GeV with an integrated luminosity of 104 $\mathrm{pb}^{-1}$, which is the largest data sample STAR has collected so far for such collision system and energy. In this talk, the analysis status of transverse polarization measurement of $\Lambda$/$\bar{\Lambda}$ in jets utilizing the 2015 dataset will be presented.

Speaker: Taoya Gao (Shandong University)

Transverse-DIS2022-v8.2.pdf

12:30 Longitudinal and transverse polarizations of $\Lambda$ hyperon in unpolarized SIDIS and $e^+ e^-$ annihilation

We make a systematic study of $\Lambda$ hyperon polarizations in unpolarized lepton induced semi-inclusive reactions such as $e^-N\to e^-\Lambda X$ and $e^+e^-\to\Lambda h X$. We present the general form of cross sections in terms of structure functions obtained from a general kinematic analysis. This already shows that the produced hyperons can be polarized in three orthogonal directions, i.e., the longitudinal direction along the hyperon momentum, the normal direction of the production plane, and the transverse direction in the production plane. We present the parton model results at the leading twist and leading order in perturbative QCD using transverse momentum dependent factorization and provide the expressions for these structure functions and polarizations in terms of three dimensional parton distribution functions and fragmentation functions. We emphasize in particular that by studying the longitudinal polarization and the transverse polarization in the production plane, we can extract the corresponding chiral-odd fragmentation functions $H_{1Lq}^{\perp\Lambda}$, $H_{1Tq}^{\Lambda}$ and $H_{1Tq}^{\perp\Lambda}$. We also present numerical results of rough estimates utilizing available parameterizations of fragmentation functions and approximations. We discuss how to measure these polarizations and point out in particular that they can be carried out in future EIC and/or $e^+e^-$ annihilation experiments such as Belle.

Speaker: Prof. Yukun Song (University of Jinan)

Song-DIS2022-v2.pdf

12:50 Forward neutron single spin asymmetries in proton-proton and proton-nucleus collisions

Forward neutron single spin asymmetries in proton-proton collisions have
been discovered in early polarized RHIC running and have since been used
as local polarimetry by the RHIC experiments. Its creation mechanism can
be explained by the interference of pion and a1 exchange between the
polarized proton and the other hadron. However, the PHENIX experiment
discovered that the asymmetries in proton-nucleus collisions change sign
and have a larger magnitude, which can be explained by ultra-peripheral
collisions. To better understand the interplay of the two suggested
mechanisms, the data was analyzed as a function of transverse momentum
and xF and in (anti)correlation with detector activity that is sensitive
to the presence or absence of hard collisions.
The results for proton-proton, proton-Aluminum and proton-Gold
collisions will be presented and compared to model predictions including
both mechanisms.

Speaker: Ralf Seidl

2022_05_05_DIS_PHENIX_ZDC.pdf

13:10 Transverse single spin asymmetry measurement for very forward neutron production at the RHICf experiment

In the high-energy $p + p$ collisions, the transverse single spin asymmetry for very forward neutron production was measured by the PHENIX experiment at three different collision energies, 62, 200, and 500 GeV. It has been explained by an interference between $\pi$ (spin-flip) and $a_1$ (spin non-flip) exchange with a non-zero phase shift. In June 2017, the RHICf experiment has measured the very forward neutron asymmetry at $\sqrt{s} = 510$ GeV by installing a new sampling calorimeter at the zero-degree area of the STAR experiment. In this talk, we present the result for the single spin asymmetry for very forward neutron production as functions of longitudinal momentum fraction and transverse momentum covering up to the highest transverse momentum ever measured, about 1 GeV/$c$. Recently, the asymmetry measured by the PHENIX experiment at 200 GeV was unfolded and shown to increase in magnitude with the transverse momentum without a clear longitudinal momentum fraction dependence. The neutron asymmetry measured by RHICf at 510 GeV and that by PHENIX at 200 GeV can be compared ant the validity of the $\pi$ and $a_1$ exchange model can also be tested in a wider transverse momentum coverage.

Speaker: Dr Kim Minho (RIKEN)

DIS2022.pdf

proceeding.pdf

08:40 → 11:30 WG4: QCD with Heavy Flavours and Hadronic Final States: Quarkonia and Exotics

Conveners: Maria Vittoria Garzelli, Olga Evdokimov (University of Illinois at Chicago (US)), Xuan Li (Los Alamos National Laboratory)

08:40 Jet shapes in H/V+jet with kt clustering at hadron colliders

We present calculations of the invariant mass of the leading highest-p$_t$ jet in the production of Higgs/vector bosons in association with a single hard jet at hadron colliders. We pay particular attention to the structure of non-global logarithms both at fixed-order and to all-orders in QCD perturbative expansion. Our calculations are carried out in the eikonal (soft) approximation, and hence valid to single-log accuracy, for jets defined with k$_t$ clustering. The analytical all-orders resummed formula is matched to MCFM NLO fixed-order distribution and compared to both Pythia and Herwig event generators. Including an approximation to non-perturbative effects the final result is compared to CMS experimental data for the particular Z+jet process. Good agreements have been found for all the said comparisons over a wide range of the observable.

Speaker: Dr Kamel Khelifa-Kerfa (Université de Relizane)

DIS22_KK.pdf

DIS22_proc.pdf

09:00 Kinematics dependent jet transport coefficient in cold nuclear matter

Extracting the non-perturbative transport coefficient $\hat q$ is an important approach to quantify the nuclear medium property probed by the jets traversing the medium. Electron-nucleus (eA) and proton-nucleus (pA) collisions provide a clean environment to delicately study the jet transport coefficient in cold nuclear matter and to test the theoretical framework of jet-medium interaction, and may in turn be instructive for the study of quark-gluon plasma (QGP).

Within the theoretical framework of the higher-twist expansion, we perform the first global extraction of the $\hat q$ in cold nuclear matter from the experimental data mainly on various types of transverse momentum broadening in eA and pA collisions. Our global analysis suggests a universal $\hat q$ in cold nuclear matter as a function of Bjorken $x$ and probing scale $Q^2$. Moreover, this kinematic dependence can be converted into the jet energy dependence, which is of great interest in the study of jet quenching in QGP.

Utilizing the extracted $\hat q(x,Q^2)$ and its uncertainty determined from a Hessian analysis, we further study relevant observables in future experiments of electron-ion collisions (EIC), including the transverse momentum broadening for single hadron and heavy-quarkonium ($J/\psi$) productions, as well as the nuclear enhancement of the transverse momentum imbalance for di-hadron and heavy-meson ($D\bar D$) pair productions. The future EIC is expected to provide a more precise understanding of the kinematic dependence of the $\hat q$ in cold nuclear matter due to the wide kinematic coverage and high-precision measurements.

Speaker: Peng Ru (South China Normal University)

Ru_DIS2022.pdf

Ru_DIS2022_proceedings.pdf

09:20 A simple model to include initial-state and hot-medium effects in the computation of quarkonium nuclear modification factor

Quarkonium suppression is one of the more useful observables to obtain information about the hot medium created in ultrarelativistic heavy-ion collisions.
In this talk, we discuss a simple way to implement both the initial-state effects and the hot-medium evolution, and to compute the quarkonium nuclear modification factor if the survival probability for a bound state at a given energy density is known.
Based on the Glauber model, the temperature of the evolving medium and the centrality dependence of the nuclear modification factor will be analysed.

Speaker: Miguel Ángel Escobedo (USC)

dis2022_escobedo.pdf

09:41 $\Upsilon$ polarization in pp and J/$\Psi$ polarization as a function of event plane in Pb--Pb with ALICE at the LHC

Polarization and spin-alignment measurements represent an important tool to understand the particle production mechanisms in proton-proton (pp) collisions. In heavy-ion collisions, quarkonium polarization could also be used to investigate the characteristics of a deconfined state of nuclear matter, the quark--gluon plasma (QGP), created at LHC energies. This measurement was performed for the first time in nucleus-nucleus collisions by ALICE, and a significant difference was found with respect to the LHCb results in pp collisions at $\sqrt{s} = 7$ TeV. This difference could be related to the modification of the J/$\Psi$ feed down fractions, due to the suppression of the excited states in the QGP, or to the contribution of the regenerated J/$\Psi$ in the low transverse momentum region. Moreover, it has been hypothesized that quarkonium states could be polarized by the strong magnetic field, generated in the early phase of the evolution of the system, and by the large angular momentum of the medium in non-central heavy-ion collisions. This kind of information can be assessed by defining an ad hoc reference frame where the quantization axis is orthogonal to the event plane of the collision.

In this contribution, the final ALICE measurement of inclusive J/$\Psi$ polarization with respect to the event-plane in Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02$ TeV and the latest $\Upsilon$(1S) polarization measurement in pp collisions at $\sqrt{s} = 13$ TeV will be presented. Both measurements are performed at forward rapidity with the muon spectrometer of ALICE, via the measurements of the angular anisotropy of their decay products.

Speaker: Ms Yanchun Ding (CCNU; IP2I)

dDIS2022_final.pdf

10:00 Heavy flavor and exotic production at LHCb

Charm and bottom quark production is an important experimental observable that sheds light on the heavy quark interaction with the nuclear medium. With high statistics datasets, tracking and PID at very low transverse momentum, and excellent vertexing capabilities, LHCb performs precision measurements of a rich set of heavy flavor hadrons, including B mesons, open charm hadrons and charmonia. These capabilities allow for precise studies of strangeness enhancement, baryon enhancement, and charmonia suppression in various colliding systems from $pp$ to $p$Pb and PbPb. Furthermore, the production of the exotic $X$(3872) and $T_{cc}^{+}$ hadrons in $pp$ and $p$Pb collisions is also studied. The nuclear modification factor $R_{pA}$ for the four-quark state $X$(3872) is measured for the first time. We will present these results along with comparisons to theoretical calculations.

Speaker: Sara Sellam

sarasellam_DIS2022.pdf

10:20 Probing exotic states in photon - induced interactions at the LHC

In the last few years many exotic hadrons, which are states which do not appear to fit with the expectations for an ordinary $q\bar{q}$ or $qqq$ hadrons in the quark model, have been observed at various experimental facilities. Such results have motivated a series of studies focused on the description of the internal structure of the exotic hadrons as well as the proposition of new channels to search and constrain the properties of these states. In particular, the study of hidden - heavy quark pentaquarks and fully heavy tetraquark states have received a lot of attention. In this contribution, I will present an overview of the recent results obtained by our group that demonstrated that the pentaquark states $P_c$ and $P_b$ as well as the fully - heavy tetracharm states $T_{4c}$ can be probed in photon - induced interactions at the LHC. In particular, these studies indicate that the study of $\gamma h$ and $\gamma \gamma$ interactions at LHC can also provide complementary and independent checks on the properties of exotic states, and help to understand their underlying nature.

Speaker: Victor Gonçalves (Universidade Federal de Pelotas)

Talk_DIS22_Exotic_VPG.pdf

10:40 Electromagnetic structure of heavy baryons

We obtain the masses, the electromagnetic properties, and the parton distribution functions (PDFs) of the baryons (with a strange quark $\Lambda$ and a charm quark $\Lambda_c$, and their isospin triplet baryons) from a light-front effective Hamiltonian in the leading Fock sector. The effective Hamiltonian consists of the confining potential adopted from light-front holography in the transverse direction, longitudinal confinement, and a one-gluon exchange interaction with fixed coupling. The electromagnetic radii and the magnetic moments are found to be consistent with the available experimental data. We also show a comparison with the other theoretical calculations on the electromagnetic properties of these baryons. We present the gluon and the sea quark PDFs which we generate dynamically from the QCD evolution of the valence quark distributions.

Speaker: Tiancai Peng

DIS2022 Tc Peng.pdf

11:00 Coffee-break

08:40 → 13:30 WG6: Future Experiments: Session 3

Conveners: Alessandro Polini (Universita e INFN, Bologna (IT)), Michela Chiosso (University of Torino and INFN), Yulia Furletova

08:40 SIDIS reconstruction and observables at EIC with ATHENA

ATHENA (A Totally Hermetic Electron-Nucleus Apparatus) is a proposed detector system for the future Electron-Ion Collider. This talk will focus on the physics program using semi-inclusive deep-inelastic scattering. In particular the expected performance of the detector and novel reconstruction methods for SIDIS variables. Extensions of these methods using ML methods will be presented as well. Additionally, we will discuss the projected resolution of gluon saturation observables with ATHENA, specifically through the measurement of away-side suppression of dihadrons at low-x.

Speaker: Connor Pecar

dis2022_pecar.pdf

SIDIS_ML_DIS22.pdf

09:00 PERLE: The development of a multi-turn, high current ERL

The realisation of the LHeC and the FCC-he at CERN require the development of the energy recovering technique in multipass mode and for large currents $\mathcal{O}(10)$ mA in the SRF cavities. For this purpose, a technology development facility, PERLE, is under design to be built at IJCLab Orsay, which has the key LHeC ERL parameters in terms of configuration, source, current, frequency and technical solutions, cryomodule, stacked magnets. In this talk we review the design and comment on the status of PERLE.

Speaker: achille stocchi (IJCLab , UNiversite Paris-Saclay, CNRS)

PERLE-DIS-Santiago-sans-backup.pdf

09:20 A common $eh/hh$ interaction region and detector for the LHC

In this talk we present initial accelerator considerations on a common IR to be built which alternately could serve $eh$ and $hh$ collisions at the HL-LHC, while other experiments would stay on $hh$ in either condition [1]. A forward-backward symmetrised option of the LHeC detector is sketched which would permit extending the LHeC physics programme to also include aspects of hadron-hadron and heavy ion physics.

[1] K. D. J. Andre et al., An experiment for electron-hadron scattering at the LHC, Eur. Phys. J. C 82 (2022) 1, 40, e-Print: 2201.02436 [hep-ex].

Speaker: Kevin Daniel Joel Andre (CERN)

DIS2022 - LHeC .pdf

DIS2022 - LHeC .pptx

09:40 Unraveling non-linear parton dynamics at small $x$ through high energy $ep$ and $e$A scattering

The LHeC and the FCC-he will measure DIS cross sections in an unprecedented range of small $x$ where the non-linear dynamics expected in the high energy regime of QCD should be relevant in a region of small coupling. In this talk we will demonstrate the unique capability of these high-energy colliders for unravelling dynamics beyond fixed-order perturbation theory, proving the non-linear regime of QCD, saturation, to exist (or to disprove). This is enabled through the simultaneous measurements, of similar high precision and range, of $ep$ and $e$A collisions which will eventually disentangle nonlinear parton-parton interactions from nuclear environment effects.

Reference: P. Agostini et al. (LHeC Study Group), The Large Hadron-Electron Collider at the HL-LHC, J. Phys. G 48 (2021) 11, 110501, e-Print: 2007.14491 [hep-ex].

Speaker: Anna Stasto

Anna_Stasto_lhec_fcceh.pdf

10:00 Exploring the origin of the EMC effect with electron-deuteron DIS and spectator nucleon tagging at EIC

The origin of the nuclear modifications of partonic structure at $x > 0.3$ (EMC effect) observed in DIS experiments remains one of the major open questions of nuclear physics. Inclusive nuclear DIS experiments observe only the average effect and do not provide information about the underlying nuclear interactions. Major progress can come from DIS on the deuteron with spectator nucleon tagging, where the nuclear configuration during the DIS process is fixed by the spectator momentum and the nuclear modifications can be studied differentially in the relative momentum/distance between the nucleons. We report about simulations of a systematic study of the EMC effect using deuteron DIS with spectator nucleon tagging at the EIC. The BeAGLE event generator is supplied with a minimal virtuality-dependent parametrization of the tagged EMC effect constrained by theory and inclusive nuclear DIS data. Proton and neutron spectator tagging is simulated with the EIC far-forward detectors in the present IP6 and IP8 configurations (extending earlier results reported in [1]). An analysis strategy for the tagged EMC effect is outlined (observables, separation of initial- and final-state effects), and the uncertainties and impact of the measurements is quantified.

[1] A. Jentsch, Zhoudunming Tu, C. Weiss, Phys.Rev.C 104 (2021) 6, 065205

Speaker: Zhoudunming Tu

DIS_05_05_2022_ZT-v3.pdf

10:20 Exclusive Lepton Pairs at the Electron-Ion Collider

Two-photon exclusive production of lepton pairs at the Electron-Ion Collider opens interesting research directions thanks to a very high luminosity and clean experimental conditions at the EIC. First estimates of scientific potential for such studies are given. In particular, they consider unique measurements of the proton and ion electromagnetic form-factors,and searches of anomalous couplings of $\tau$ leptons.

Speaker: Krzysztof Piotrzkowski

DIS_2022_KP.pdf

10:40 High energy photon-photon interactions at the LHeC and FCC-eh

Novel studies of high energy photon-photon interactions at the LHeC [1] and FCC-eh, at the center-of-mass energy up to 1 TeV and beyond, will open new frontiers in the electroweak physics as well as in searches for physics beyond the Standard Model. Despite very high ep luminosities, the experimental conditions will be very favorable at these colliders - a negligible event pileup will allow for unique studies of a number of processes involving the exclusive production via photon-photon fusion.

The exclusive two-photon production of W, Z, photon and tau pairs at the LHeC and FCC-eh has been benchmarked and is discussed in this paper, along with first estimates of sensitivities to physics beyond the Standard Model expected for the measurements of such processes.

__

[1] https://arxiv.org/abs/2109.08001

Speakers: Krzysztof Piotrzkowski (AGH UST Krakow), Yuji Yamazaki (Kobe University)

DIS_KP.pdf

11:00 Coffee break

09:00 → 13:30 WG1: Structure Functions and Parton Densities: Session 3

Conveners: Barak Schmookler (Stony Brook University), Klaus Rabbertz (KIT - Karlsruhe Institute of Technology (DE)), Thomas Cridge (University College London)

09:20 Moments of the longitudinal structure function of proton from lattice QCD simulations

Recently, the $Q^2$ dependence of several low moments of the proton longitudinal structure function, $F_L$, has been mapped thanks to the measurements taken at HERA and JLAB. In this contribution, we present the first lattice QCD determination of the lowest moment of $F_L$ and its $Q^2$ dependence. This is achieved by computing the forward Compton amplitude via an application of the second-order Feynman-Hellmann method. We show the moments of $F_1$, $F_2$, and $F_L$ in comparison to experimental values and discuss future directions.

Speaker: Dr K. Utku Can (The University of Adelaide)

Can_DIS2022.pdf

09:40 Recent Lattice-QCD Calculations of Parton Distributions

There have been rapid developments in direct lattice-QCD calculations of the Bjorken-x dependence of parton distributions. In this talk, I will highlight selected recent lattice-QCD results on parton distributions with emphasis on calculations at physical pion mass when applicable. Results include the continuum-physical isovector nucleon PDF, a first study of the strange and charm PDFs, the pion and kaon valence-quark PDFs, and progress made in gluon PDFs and GPDs.

Speaker: Huey-Wen Lin

hwlin_DIS-talk.pdf

10:00 The extraction of light cone parton distributions from lattice quantum chromodynamics

The light-cone definition of Parton Distribution Functions (PDFs) does not allow for a direct ab initio determination employing methods of Lattice QCD simulations that naturally take place in Euclidean spacetime. In this presentation we focus on pseudo-PDFs where the starting point is the equal time hadronic matrix element with the quark and anti-quark fields separated by a finite distance. We focus on Ioffe-time distributions, which are functions of the Ioffe-time ν, and can be understood as the Fourier transforms of parton distribution functions with respect to the momentum fraction variable 𝑥. We present lattice results for the case of the nucleon and the pion addressing among others the physical point and continuum extrapolations. We also incorporate our lattice data in the NNPDF framework treating them on the same footing as experimental data and discuss in detail the different sources of systematics in the determination of the non-singlet PDFs.
Finally, we will present the latest results of the HadStruc collaboration on the gluon and transversity PDF of the nucleon.

Speaker: Savvas Zafeiropoulos

ZafeiropoulosDIS22.pdf

10:20 Complementarity of experimental and lattice QCD data on pion parton distributions

Recent reduced pseudo Ioffe time distributions and matrix elements of current-current correlators generated from lattice QCD are used simultaneously with experimental data to extract pion parton distribution functions (PDFs) from a Monte Carlo global QCD analysis. Through the complementarity of the experimental and lattice QCD data, the analysis rigorously quantifies both the uncertainties of the pion PDFs and systematic effects intrinsic to the lattice QCD observables.
The reduced pseudo Ioffe time distributions significantly decrease the uncertainties on the PDFs, while the current-current correlators are limited by the systematic effects associated with the lattice. Consistent with recent phenomenological determinations, the behavior of the valence quark
distribution of the pion at large momentum fraction is found to be $\sim(1−x)^{\beta_{\rm eff}}$ with $\beta_{\rm eff} \sim 1.0−1.2$.

Speaker: Patrick Barry

Barry_JAMlat.pdf

10:40 Pion parton distribution function in Minkowski space

In this contribution, I will present a novel dynamical model for the pion based on the solution of the Bethe-Salpeter equation in Minkowski space. Our approach considers the pion as a bound state of a pair quark anti-quark interacting through the one-gluon exchange. The inputs of the model are the quark and gluon masses, and a scale parameter related to the extended quark-gluon vertex. Within this model, we obtain the full parton distribution function (PDF) directly in Minkowski space, as well as the contribution from the light-front valence state. We also present a comparison with experimental data, after evolving the PDF at the initial scale. In addition, we compute other hadronic observables, as the pion weak decay constant, the valence probability, the LF-momentum distributions, the distribution amplitude, the probability densities both in the LF-momentum space and in the 3D space given by the Cartesian product of the covariant Ioffe-time and transverse coordinates [1]. Furthermore, we show results for the pion electromagnetic form factor which presents a good agreement with available experimental data [2].

References:
1. W. de Paula, E. Ydrefors, J. H. Alvarenga Nogueira, T. Frederico and G. Salme, Phys. Rev. D 103 (2021) no.1, 014002
2. E. Ydrefors, W. de Paula, J. H. A. Nogueira, T. Frederico and G. Salme, Phys. Lett. B 820 (2021), 136494

Speakers: wayne de paula, Emanuel Ydrefors (Instituto Tecnologico de Aeronautica)

dePaula_DIS.pdf

11:00 Coffee break

11:30 Gluon distributions in light mesons on the light front

We obtain the light meson light-front wavefunctions (LFWFs) from the light-front QCD Hamiltonian, determined for their constituent quark-antiquark and quark-antiquark-gluon Fock components, together with a three-dimensional confinement. By fitting the model parameters to achieve the light-meson mass spectroscpy, the LFWFs provide a good quality description of the pion electromagnetic form factor, decay constant, and the valence quark distribution functions following QCD scale evolution. We further employ the LFWFs to compute the gluon PDFs, GPDs and TMDs in the light mesons.

Speakers: Jiangshan LAN (Institute of Modern Physics, CAS), Mr Jiatong Wu (Institute of Modern Physics, Chinese Academy of Sciences)

DIS2022JLAN2.pdf

DIS2022JLAN2.pptx

11:50 Impact of Physical Scheme heavy-quark mass corrections on DIS PDF fits

We describe the phenomenological implications of a new heavy-quark mass scheme, called the Physical Scheme, that accounts for the effects of intrinsic heavy-quarks and provides a way to smoothly transition over the heavy-quark thresholds. We will present results for the DIS coefficient functions for $F_2$ and $F_L$ at NLO in the Physical Scheme showing that they reduce to the familiar (massless) $\overline{\text{MS}}$ ones in the limit of large $Q^2$, where $Q^2$ is the virtuality of the DIS probe. We end by showing some preliminary results on the effect of extracting parton distribution functions in the Physical Scheme using the HERA structure function data that spans a wide range of momentum fractions $x$ and scales $Q^2$.

Speaker: Chris Flett

DIS22_talk2_cflett.pdf

flett_DIS22_proc_wg1.pdf

12:10 Intrinsic Charged-Current DIS at NNLO QCD

Heavy flavor mass effects are significant in deep inelastic scattering (DIS) processes, and their systematic treatment becomes of more importance as we approach a one-percent accuracy in the determination of Parton Distribution Functions (PDFs). These effects are included through so-called variable flavor number schemes (VFNS), and most of the ingredients that are required by these schemes have been calculated in the past at next-to-next-to-leading order (NNLO) QCD. However, one ingredient, and we refer to it as the intrinsic charged-current DIS, is still missing
$$c+W^{-}\to s + X,$$ where $c$ is a heavy (massive) flavor, and $s$ is a light (massless) one.

In this talk, we present the calculations of the intrinsic charged-current DIS structure functions at NNLO QCD with exact initial heavy flavor mass dependence. We discuss the peculiarities of these calculations. Furthermore, we discuss the importance of our result for the study of the intrinsic charm component of PDFs. These calculations pave the way to the systematic evaluation of theoretical uncertainties that are associated with heavy flavor mass effects in PDFs at NNLO QCD and beyond.

Speaker: Kirill Kudashkin

DIS2022.pdf

12:30 The 3-loop anomalous dimensions from off-shell operator matrix elements

The anomalous dimensions of local quark and gluon operators determine the
scaling violations of the deep–inelastic scattering structure functions
and are therefore instrumental in the measurement of the strong coupling constant
and the evolution of the parton densities.
In this talk I present our recalculation of the 2- and 3-loop
anomalous dimensions with the traditional method of off-shell
operator matrix elemements.
I present results in the polarized and unpolarized non-singlet case,
the polarized singlet case, as well as recent progress in extendending the
calculation to the unpolarized singlet case.

Speaker: Kay Schönwald

DIS_2022.pdf

12:50 DIS at 4-loops with differential equations

The computation of the structure functions for DIS can be tested across a range of energies with high accuracy and provides vital information for the evolution in the distribution of partons within a proton. We are currently investigating DIS at 4-loop, in particular the non-singlet sector.

Our approach consists of the determination large number of Mellin Moments, allowing for the reconstruction of the structure functions. This expansion is performed at the level of master integrals and through a novel system of expansion via differential equations.

We have started by considering $n_f^2$ contributions, obtaining an expansion up to N=1500, for the derivation of the corresponding coefficient functions.
We aim at pushing our efforts beyond that and compute new contributions to the 3-loop splitting functions, in particular, corrections corresponding to $C_f^3n_f$.

Speaker: Andrea Pelloni (Nikhef)

dis_pelloni.pdf

13:10 Studying nuclear matter with jets in the sPHENIX experiment at RHIC

The sPHENIX detector currently under construction at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) is designed to significantly advance studies of the microscopic nature of nuclear matter. The experiment incorporates full azimuth vertexing, tracking, and a complete set of electromagnetic and hadronic calorimeters over the pseudorapidity range |η| < 1.1. This powerful detector system is coupled with a high rate DAQ in order to deliver unprecedented data sets enabling a wide range of jet measurements at RHIC. SPHENIX has an extensive a multi-year physics program planned which includes Au+Au, polarized p+p and p+Au collisions. Measurements of jets and jet substructure in these systems will provide unprecedented access to nuclear PDFs and the spin-orbit correlations in the proton through measurements of the Sivers and Collins asymmetries. In this talk we will present an overview of the sPHENIX jet measuring capabilities and the planned sPHENIX jet physics program.

Speaker: John Lajoie

studying nuclear matter with jets in the sphenix experiment at rhic rev12.pdf

09:00 → 13:30 WG2: Small-x, Diffraction and Vector Mesons: Session 3

Conveners: Daria Sokhan (CEA Saclay / Glasgow U.), Guillaume Beuf, Rafał Staszewski (IFJ PAN Cracow (PL))

09:40 Forward Single Inclusive Jet Production in pA Collisions at Next-to-leading Order with Threshold Resummation

My talk is baesed on our work of presenting the first complete next-to-leading-order (NLO) prediction for the single inclusive jet production in pA collisions at forward rapidities within the color glass condensate (CGC) effective theory. Our prediction is fully differential over the final state physical kinematics, which allows the implementation of the full jet clustering algorithm in our calculation, as well as any other infra-red safe observables. The NLO calculation is setup with the aid of the observable originated power counting framework we proposed which gives rise to the novel soft contributions in the CGC factorization. We achieve the fully-differential calculation by constructing suitable subtraction terms to handle the singularities in the real corrections. The subtraction contributions can be exactly integrated analytically. The NLO calculation demonstrates explicitly the validity of the CGC factorization theorem to the jet production. Furthermore, as a byproduct of the subtraction method, we also derive the fully analytic cross section for the forward jet production in the small-R limit. We show that in the small-R limit, the forward jet cross section can be factorized to a semi-hard cross section that produces a parton and the semi-inclusive jet function (siJF),just like the jet production in the central region where exactly the same siJF shows up. We argue this feature holds for generic jet productions in the CGC framework. Last, we show numerical predictions of the jet transverse momentum and energy distributions. Like the forward hadron production, the obtained NLO result also exhibits the negative cross section in the large jet transverse regime, this talk also contains our solution to this which is the threshold resummation.

Speaker: Hao-yu Liu

Single Inclusive Jet Production in pACollisions at NLO.pdf

10:00 Heavy quarkonium production via matching of High Energy Factorization and NLO of Collinear Factorization

The energy dependence of the total inclusive hadroproduction cross section of pseudo-scalar quarkonia and photoproduction cross section of vector quarkonia is computed via matching Next-to-Leading Order (NLO) Collinear-Factorisation (CF) results with resummed higher-order corrections, proportional to $\alpha_s^n ln^{n-1} (1/z)$, to the CF hard-scattering coefficient, where $z=M^2/\hat{s}$ with M and ŝ being the quarkonium mass and the partonic center-of-mass energy squared. The resummation is performed using High-Energy Factorisation (HEF) in the Doubly-Logarithmic (DL) approximation, which is a subset of the leading logarithmic ln(1/z) approximation. Doing so, one remains strictly consistent with the NLO and NNLO DGLAP evolution of the PDFs. By improving the treatment of the small-z asymptotics of the CF coefficient function, the resummation cures the unphysical results of the NLO CF calculation. The matching is directly performed in the z-space and, for the first time, by using the Inverse-Error Weighting (InEW) matching procedure. As a by-product of the calculation, the NNLO term of the CF hard-scattering coefficient proportional to $\alpha_s^2 ln(1/z)$ is predicted from HEF.

Based on hep-ph/2112.06789 and ongoing work.

Speaker: Dr Maxim Nefedov (NCBJ, Warsaw)

Nefedov_DIS-2022.pdf

10:20 Inclusive J/Ψ and Υ emissions from single-parton fragmentation in hybrid high-energy and collinear factorization

We present a novel study on the inclusive production of a heavy quarkonium (J/Ψ or Υ), in association with a light-flavored jet, as a test field of the high-energy QCD dynamics. The large transverse momenta at which the two final-state objects are detected permits to perform an analysis in the spirit of the variable-flavor number scheme (VFNS), in which the cross section for the hadroproduction of a light parton is convoluted with a perturbative fragmentation function that describes the transition from a light quark to a heavy hadron.
The quarkonium collinear fragmentation function is build as a product between a short-distance coefficient function, which encodes the resummation of DGLAP type logarithms, and a non-perturbative long-distance matrix element (LDME), calculated in the framework of the non-relativistic QCD (NRQCD). Our theoretical setup is the hybrid high-energy and collinear factorization, where the standard collinear approach is supplemented by the resummation of leading and next-to-leading energy-type logarithms `a la BFKL. We propose this reaction as a suitable channel to probe the production mechanisms of quarkonia at high energies and large transverse momenta and to possibly unveil the transition region from the heavy-quark pair production mechanism to the single-parton fragmentation one.

Speaker: Michael Fucilla

FucillaDIS2022.pdf

Proceeding_DIS_2022_JPsi_Y_jet_SPF_Fucilla.pdf

10:40 Hybrid kT-factorization at NLO

Factorization formulas for scattering cross sections typically involve a parton-level cross section and PDFs associated with scattering hadrons. In hybrid kT-factorization, one PDF depends on the transverse momentum components of the parton besides the momentum component longitudinal to the hadron momentum. Furthermore, also in the partonic cross section these transverse components are not neglected. We present a scheme for this factorization at next-to-leading order for gluon-initiated processes involving an arbitrary number of final-state jets.

Speaker: Andreas van Hameren

vanHameren.pdf

vanHamerenProceedings.pdf

11:00 Coffee break

11:30 Fitting the dipole amplitude with collinearly improved JIMWLK equation

I summarize our attempts to describe HERA experimental data for the F_2 structure function using our implementation of the collinearly improved JIMWLK equation. I briefly describe the numerical framework based on Langevin reformulation of the JIMWLK equation and I illustrate the impact of the improvement on the dipole amplitude. I also comment on the influence of different functional forms of the initial condition.

Speaker: Dr Piotr Korcyl (Jagiellonian University)

KORCYL_DIS_2022_talk.pdf

11:50 NLO JIMWLK equations with massive quarks

Based on the light-cone wave function approach, we derive the the JIMWLK evolution equations with massive quarks. This is a generalization of previous work of NLO JIMWLK with massless quarks. The introduction of quark mass not only complicates relevant integrals due to massive energy denominators (propagators), but also gives rise to some divergences that are not present for cases with massless quarks, which needs to be carefully dealt with.

Speaker: Dr Lin Dai

DIS-2020-Dai.pdf

12:10 Unifying approaches: Balitsky and effective action of Lipatov

We consider a derivation of the hierarchy of correlators of ordered exponentials directly from the Lipatov's effective action
formulated in terms of interacting ordered exponentials.
The derivation of the Balitsky equation from the hierarchy is discussed as well as
the way the sub-leading eikonal corrections to the Balitsky equation arise from the transverse field contribution and sub-leading eikonal corrections to the quark propagator.

Speaker: Prof. Sergey Bondarenko (Ariel university, Israel)

SantiagoLipatovBAlitskyAction_1.pdf

12:30 Exploring Pomeron interactions in the toy world

We discuss models with Pomeron interactions in zero transverse dimensions. We show how to construct unitary models that allow for emission of more than one parton in one step of high energy evolution, and study some properties of particle distributions in these models.

Speaker: Michael Lublinsky (BGU)

DIS2022.pdf

09:00 → 13:30 WG3: Electroweak Physics and Beyond the Standard Model: Session 3

Conveners: Adam Orion Martin (University of Notre Dame (US)), Heather Gray (UC Berkeley/LBNL), Heidi Angelika Rzehak

09:00 Unconventional thermal(-ish) dark matter

Thermal dark matter candidates are usually associated with the Weakly-interacting massive particles (WIMPS). However, vanilla WIMP scenarios suffer from severe experimental constraints. I would therefore like to discuss two alternatives to the standard picture: Inelastic Dark Matter and Dark Sectors with Bound States. In both cases, a dark matter candidate is in thermal contact with the Standard Model plasma at high temperatures, but its decoupling differs sufficiently from the one of a WIMP. This drastically changes the relic abundance predictions and thus changes dark matter phenomenology, opening the playground for new searches.

Speaker: Anastasiia Filimonova (Nikhef)

Filimonova-DIS2022.pdf

09:20 Results related to anomalies at Belle II

Decays of B mesons that proceed through electroweak and radiative penguin amplitudes currently attract significant attention due to a number of observed discrepancies between the standard model predictions and the experimental results.
Belle II is expected to perform measurements on channels closely related to those exhibiting anomalies and that are uniquely available to Belle II. These include b -> s(d) nu nubar and b -> s(d) tau+ tau- transitions. We present the first signals observed with early data on b -> s gamma, b -> s l+ l- transitions, and discuss the limits on B+ -> K+ nu nubar obtained with a novel inclusive technique. In addition, semi-tauonic decays are showing tensions with the standard model predictions. The progress towards the first measurements of B->D(*)tau nu are also presented.

Speaker: Martin Angelsmark

MartinAngelsmark_AnomaliesAtBelle2.pdf

09:40 Status and prospects of new Physics searches with the MEG-II experiment

The search for lepton flavour violation is regarded as one of the main roads in the quest for new physics beyond the Standard Model. At PSI, Switzerland, the MEG II experiment will search for the $\mu \rightarrow e \gamma$ decay with the capability of setting an upper limit down to $6 \times 10^{-14}$, one order of magnitude below the result of the first-phase MEG experiment. The MEG II detector is an integral upgrade of MEG, with increased granularity and improved resolutions in all sub-detectors, and the integration of additional instrumentation for background rejection and calibrations. The 2021 run has been successfully completed and another physics run is forseen in 2022. I will present the current status of this experimental effort, its prospects and its potential beside the $\mu \rightarrow e \gamma$ search. In particular, it is possible to search for the X17 anomaly observed by the Atomki experiment in Li+p reactions, with the Cockroft Walton accelerator routinely used in calibrations, and the MEG II detector.

Speaker: Dr Cecilia Voena (Sapienza Universita e INFN, Roma I (IT))

Voena_DIS2022.pdf

10:00 The phenomenological cornucopia of SU(3) exotica

We introduce an effort to catalog the gauge-invariant interactions of Standard Model (SM) particles and new fields in a variety of representations of the SM color gauge group SU(3)c. In this first installment, we direct this effort toward fields in the six-dimensional (sextet, 6) representation. We consider effective operators of mass dimension up to seven (comprehensively up to dimension six), featuring both scalar and fermionic color sextets. We use an iterative tensor-product method to identify the color invariants underpinning such operators, emphasizing structures that have received little attention to date. In order to demonstrate the utility of our approach, we study a simple but novel model of color-sextet fields at the Large Hadron Collider (LHC). We compute cross sections for an array of new production channels enabled by our operators, including single-sextet production and sextet production in association with photons or leptons. We also discuss dijet-resonance constraints on a sextet fermion. This example shows that there remains a wide array of fairly minimal but well motivated and unexplored models with extended strong sectors as we await the high-luminosity LHC.

Speaker: Linda Carpenter

DIS2022.pdf

10:20 Looking for a Muonic Force in the Muon Anomalies

Significant deviations from SM predictions have been observed in $ b \to s \mu^+ \mu^-$ decays and in the muon (g-2). Scalar leptoquark extensions of the SM are known to be able to address these anomalies, but generically give rise to lepton flavor violation or even proton decay. As a possible resolution, we introduce a lepton-flavored U(1) gauge symmetry to preserve the accidental symmetries of the SM. It is natural to consider the possibility that the gauge boson of this new force can account for the muon g-2, without the introduction of additional particles. An array of complementary constraints, including neutrino trident production and nonstandard neutrino interaction, rules out all but a few possible gauge groups as solutions to the muon g-2.

Speaker: Anders Eller Thomsen

DIS_2022.pdf

10:40 Strange quark as a probe for new physics in the Higgs sector

One of the most interesting yet-to-be answered questions in Particle Physics is the nature of the Higgs Yukawa couplings and their universality. Key information in our understanding of this question arises from studying the coupling of the Higgs boson to second generation quarks. Some puzzles in the flavor sector and potential additional sources of CP violation could also have their origins in an extended Higgs sector.
Rare Higgs decay modes to charm or strange quarks are very challenging or nearly impossible to detect with the current experiments at the Large Hadron Collider, where the large multi-jet backgrounds inhibits the study of light quark couplings with inclusive H->qqbar decays. Future e+e- machines are thus the perfect avenue to pursue this research.
Studies were initiated in the context of Snowmass2021 (https://indico.slac.stanford.edu/event/6617/contributions/1442/attachments/682/1976/SNOWMASS21-EF1_EF2-IF3_IF0_Valentina_Maria_Martina_Cairo-047.pdf) with particular emphasis on the Higgs coupling to strange quarks and the related flavour tagging challenges.

This gave light to the development of a novel algorithm for tagging jets originating from the hadronisation of strange quarks (strange-tagging) and the first application of such a strange-tagger to a direct Higgs to strange (h->ssbar) analysis. The analysis is performed with the initial hypothetical 2ab-1 of data which will be collected by the International Large Detector at the International Linear Collider during its first 10 years of data taking at sqrt(s) = 250GeV, but it is easily applicable to other Higgs factories. The study includes as well a preliminary investigation of a Ring Imaging Cerenkov system (RICH) capable of maximising strange-tagging performance in future Higgs factory detectors.

Speaker: Matthew Basso (University of Toronto (CA))

220505_Basso_DIS2022_Higgs-Strange-Tagging.pdf

11:00 Coffee break

11:30 A sensitivity study of VBS and diboson WW to dimension-6 EFT operators at the LHC

We present a parton-level study of electro-weak production of vector-boson pairs at the Large Hadron Collider, establishing the sensitivity to a set of dimension-six operators in the Standard Model Effective Field Theory (SMEFT). Different final states are statistically combined, and we discuss how the orthogonality and interdependence of different analyses must be considered to obtain the most stringent constraints. The main novelties of our study are the inclusion of SMEFT effects in non-resonant diagrams and in irreducible QCD backgrounds, and an exhaustive template analysis of optimal observables for each operator and process considered. We also assess for the first time the sensitivity of vector-boson-scattering searches in semileptonic final states. (https://inspirehep.net/literature/1901079)

Speaker: Giacomo Boldrini (Universita & INFN, Milano-Bicocca (IT))

DIS2022_Boldrini_05052022.pdf

11:50 Unbinned measurements in global SMEFT fits from machine learning

Global interpretations of particle physics data in the context of the Standard Model Effective Field Theory (SMEFT) rely on the combination of a wide range of physical observables from many different processes. We present ongoing work towards the integration of unbinned measurements into such global SMEFT interpretations by means of machine learning tools. We use a deep-learning parametrisation of the extended log-likelihood to perform an optimal unbinned multivariate analysis in the EFT parameter space, taking model uncertainties into account via the replica method. We carry out a variant of the SMEFiT global analysis using unbinned particle-level predictions of top-quark pair production and Higgs production in association with vector bosons as a proof of concept. We demonstrate the impact that such measurements would have on the EFT parameter space as compared to traditional unfolded binned measurements.

Speaker: Jaco ter Hoeve

terHoeve_DIS_2022.key

terHoeve_DIS_2022.pdf

12:10 Standard Model EFTs via on-shell methods

The talk will be about applications of on-shell techniques to the Standard Model Effective Field Theory (SMEFT). I will present a systematic classification of marginal operators in generic effective field theories and the computation of their anomalous dimensions using only on-shell data. Finally, I will show explicit results in the context of the SMEFT.

Speaker: Stefano De Angelis (Queen Mary University of London)

12:30 CP-Violating Invariants in the SMEFT

In the Standard Model, CP violation in the Electroweak sector is parametrized by the Jarlskog Invariant. This is the order parameter of CP-violation, in the sense that it vanishes iff CP is conserved. When higher dimensional operators are allowed, and the Standard Model Effective Field Theory is constructed, numerous new sources for CP violation can appear. However, the description of CP violation as a collective effect, present in the SM, is inherited by its Effective extension.
Here, I argue that such a behaviour has to be captured, at dimension 6, by flavor invariant, CP violating objects, linear in the Wilson coefficients. Such a description ensures that CP violation in the SMEFT is treated in a basis independent manner. In particular, I claim these are the objects that have to vanish, together with the SM Jarlskog Invariant, for CP to be conserved, and viceversa. The scaling properties of these invariants demonstrates that, while CP is not an accidental symmetry of the Standard Model, its breaking is accidentally small at the renormalizable level.

Speaker: Emanuele Gendy Abd El Sayed

12:50 Physics Beyond the SMEFT

Electroweak interactions assign a central role to the gauge group $SU(2)_L \times U(1)_Y$ , which is either realized linearly (SMEFT) or nonlinearly (e.g., HEFT) in the effective theory obtained when new physics above the electroweak scale is integrated out. Although the discovery of the Higgs boson has made SMEFT the default assumption, nonlinear realization remains possible.
I will discuss how the two can be distinguished through their predictions for the size of certain low-energy dimension-6 four-fermion operators. Future measurements can therefore tell us if non-SMEFT new physics is really necessary.

Speaker: Dr Jacky Kumar (Technical University Munich)

dis2022jacky.pdf

13:10 The flair of Higgsflare: distinguishing electroweak EFTs through multihiggs production

We explore the interplay between the HEFT and SMEFT theories. Whereas the SMEFT has become the standard in the field of LHC phenomenology, the HEFT provides a more flexible description of the electroweak sector. In particular, we discuss various aspects of (multi-) Higgs production from longitudinal electroweak gauge bosons $W_LW_L\to n\times h$ in the TeV region, and compare predictions from both theories.

We address the question of the SMEFT's validity, and we demonstrate how it could eventually be ruled out by comparing experimental bounds in both theories. This analysis is useful for HL-LHC and machines beyond the LHC that will reach the challenging final state with several Higgs bosons. We further inverstigate the mathematical properties of the flare function $\mathcal{F}(h)$ as an extra source of information about the Higgs vacuum.

Speaker: Dr Raquel Gomez Ambrosio (Milano Bicocca)

DIS2022_5May_RaquelGA.pdf

11:29 → 13:30 WG4: QCD with Heavy Flavours and Hadronic Final States: Heavy Flavour Future

Conveners: Maria Vittoria Garzelli, Olga Evdokimov (University of Illinois at Chicago (US)), Xuan Li (Los Alamos National Laboratory)

11:30 Heavy flavor physics with the sPHENIX detector at RHIC

In 2023, the sPHENIX detector at BNL’s Relativistic Heavy Ion Collider (RHIC) will begin measuring a suite of unique jet and heavy flavor observables with unprecedented statistics and kinematic reach at the RHIC energies using combined EM and hadronic calorimeters and high precision tracking. A MAPS-based vertex detector upgrade to sPHENIX, the MVTX, will provide a precise determination of the impact parameter of tracks relative to the primary vertex in high multiplicity heavy-ion collisions and polarized proton-proton/proton-nuclei collisions. It will enable precision measurements of open heavy-flavor observables, covering an unexplored kinematic region at RHIC. The physics program, its potential impact, and the recent detector development will be discussed in this talk.

Speaker: Sanghoon Lim (Pusan National University (KR))

DIS_shlim_HF_sPHENIX_final.pdf

11:50 Ultraperipheral collisions a thet LHC – a forerunner of the EIC small x program

We argue that a wide range of phenomena which could be studies in UPC collisions at the LHC would be able to serve as a forerunner of studies to be performed within the small x program at EIC. This includes elastic and incoherent diffractive J/ψ production off nuclei where one would be able to reach x=10-5 direct photon production of charm dijets both in inclusive and diffractive modes. Another promising process is production of leading J/ψ at large t with rapidity gap both in γp and γA scattering.In particular the γA -> ψ + gap +Y reaction would provide a unique opportunity to study propagation of a small color singlet dipole though a high density nuclear matter. Advantages of collecting information about neutron multiplicity in a ZDC are emphasized.

Speaker: Mark Strikman (Pennsylvania State University (US))

dis22upc.pdf

12:10 Hadronization and Saturation with ECCE

Future studies of nuclear physics will focus on the internal structure of the nucleon, which will require an Electron-Ion Collider (EIC) with high luminosity. Jets and heavy flavor quarks produced at the EIC will be key measurements to provide information on the hadronization process within nuclear matter, gluon saturation in nuclei, and the origin of mass. To achieve these physics goals, the ECCE consortium proposed an EIC detector based on the use of the existing Babar solenoid with a 1.4T magnet field. The performance of this physics-driven detector design was studied with an extensive set of simulations. This presentation will introduce the ECCE detector design and detail the simulation results for heavy flavor and jets which demonstrates the capabilities of the ECCE detector.

Speaker: Cheuk Ping Wong (Los Alamos National Laboratory (US))

DIS2022_HFjets_ver3.pdf

12:30 Studying Gluon Distributions and Hadronization with Heavy Flavor Production at the Future Electron Ion Collider

Heavy quark production in deep inelastic scattering receives a large contribution from the Photon Gluon Fusion process and thus provides a valuable tool to constrain the gluon distributions inside the nucleon/ion probed. Measurements of heavy flavor production can significantly improve the constraints on nuclear gluon distribution functions and gluon polarization in protons. Heavy flavor hadron pair measurements can offer direct constraints on the Transverse Momentum Dependent gluon distributions (gluon TMDs) in protons. Recent studies also propose heavy flavor hadrons as a sensitive probe to study the hadronization mechanism.

In this talk, we will present physics simulation studies of heavy flavor hadron measurements at the future EIC utilizing a silicon tracker with configuration optimized for the ATHENA detector. These studies include projections for heavy quark production with polarized and unpolarized beams to constrain gluon distribution functions in protons and ions. Heavy flavor pair production is studied through explicit reconstruction of heavy flavor hadron decays and a heavy flavor tagging algorithm utilizing displaced vertex, to constrain gluon TMDs. We show that the tagging algorithm provides good purity for heavy flavor pair reconstruction and significantly improves statistical uncertainty projections. We will also discuss prospects of utilizing heavy flavor hadron measurements to study hadronization and also the impact of detector and luminosity requirements on all these measurements

Speaker: Sooraj Radhakrishnan (LBL)

HFEIC_SR_DIS2022.pdf

12:49 Heavy flavor physics studies and silicon detector R$\&$D for the future Electron-Ion Collider

The proposed high-luminosity high-energy Electron-Ion Collider (EIC) will provide a clean environment to explore the proton/nuclear structure, search for gluon saturation and precisely determine the nuclear parton distribution functions (nPDFs) in a wide x-$Q^{2}$ phase space. Heavy flavor hadron and jet probes at the future EIC will allow us to better constrain the nPDFs within the poorly constrained high Bjorken-x region, precisely determine the quark/gluon fragmentation processes and directly study the quark/gluon energy loss within the nuclear medium. We have carried out a series of simulation studies for heavy flavor hadron and jet production in $e+p$ and $e+A$ collisions with the latest EIC conceptual detector performances. These studies include reconstructed heavy flavor hadron and jet nuclear modification factor projections, nuclear modifications on the heavy flavor hadrons inside jets, and heavy flavor jet substructures. These measurements will provide a unique path to explore the flavor dependent fragmentation functions and energy loss in heavy nuclei, which can constrain the initial and final state effects for previous and ongoing heavy ion measurements at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). A low material budget silicon vertex/tracking detector with fine spatial resolution (hit spatial resolution < 10 $\mu$m) is critical to carry out heavy flavor hadron and jet measurements at the future EIC. Fast timing capability (< 10 ns) helps suppressing backgrounds from neighboring collisions and provide precise particle identifications in the low transverse momentum region. Several advanced silicon technologies including the Low Gain Avalanche Diode (LGAD) and radiation hard Monolithic Active Pixel Sensor (MALTA) can meet these detector requirements. Progresses and results from the ongoing detector R$\&$D for LGAD and MALTA will be presented as well.

Speaker: Yasser Corrales Morales (Los Alamos National Laboratory)

DIS2022_EIC_LANL_talk_v2.pdf

13:10 Heavy flavor jet production and substructure in electron-nucleus collisions

Deep inelastic scattering on nuclei at the Electron-Ion Collider will open new opportunities to investigate the structure of matter. Heavy flavor-tagged jets are complementary probes of the partonic composition and transport coefficients of large nuclei, but introduce a new mass scale that modifies the structure of parton showers and must be carefully accounted for in perturbative calculations. In the framework of soft-collinear effective theory with Glauber gluon interactions, we present the first calculation of inclusive charm-jet and bottom-jet cross sections in electron-nucleus collisions at next-to-leading order and compare them to the reference electron-proton case. We also show predictions for the heavy flavor-tagged jet momentum sharing distributions to further clarify the correlated in-medium modification of jet substructure.

Speaker: Ivan Vitev

Vitev_DIS2022_HF.pdf

11:30 → 13:50 Joint WG1+WG6 session

Conveners: Alessandro Polini (Universita e INFN, Bologna (IT)), Barak Schmookler (Stony Brook University), Klaus Rabbertz (KIT - Karlsruhe Institute of Technology (DE)), Michela Chiosso (University of Torino and INFN), Thomas Cridge (University College London), Yulia Furletova

11:30 Probing free nucleons with (anti)neutrinos

We discuss a method to study free protons and neutrons using $\nu(\bar \nu)$-hydrogen (H) Charged Current (CC) inelastic interactions using $\nu$ and $\bar \nu$ CC interactions on both H and nuclear targets. Probing free nucleons with (anti)neutrinos provides information about their internal structure, as well as a crucial input for the modeling of $\nu(\bar \nu)$-nucleus (A) interactions. Such measurements can also represent a tool to address some of the limitations of accelerator-based neutrino scattering experiments on nuclear targets, originating from the combined effect of the unknown (anti)neutrino energy and of the nuclear smearing. We also discuss a method to impose constraints on nuclear effects and calibrate the (anti)neutrino energy scale in $\nu(\bar \nu)$-A interactions, which are two outstanding systematic uncertainties affecting present and future long-baseline neutrino experiments. The method uses $\nu(\bar \nu)$-H interactions as control samples and is based on the approach we recently proposed integrating both nuclear and ``solid" hydrogen targets within a detector designed to provide an accurate control of the configuration,chemical composition and mass of the targets.

Speaker: Roberto Petti (University of South Carolina (US))

DIS22-nuH-Petti.pdf

11:50 Prospects for measurements of the four-top-quark production cross section at the ATLAS experiment at the HL-LHC

In run 2 of the Large Hadron Collider the ATLAS experiment has found the first evidence for the four-top-quark production processes. In this contribution, we present a sensitivity study of the high-luminosity phase of the LHC to this extremely rare process with a cross section in the Standard Model of only 12 fb. Projections are given for the precision of the inclusive tttt cross section measurements in several scenarios extrapolating the run 2 measurements.

Speaker: Giancarlo Panizzo

ATL-PHYS-SLIDE-2022-094.pdf

12:10 Proton and Nuclear Collinear Parton Densities at the Electron Ion Collider using simulated ATHENA Data

The potential of the future Electron Ion Collider to constrain proton and nuclear collinear parton densities is explored using data simulated in the context of the proposed ATHENA detector. For the proton, projections relative to a `DIS-only’ approach are obtained in the HERAPDF2.0 framework. Substantial improvements in precision are observed at large x for valence quark, sea quark and gluon densities. Projections relative to the MSHT20 global fits, which also include proton-proton data from the LHC and elsewhere, show smaller improvements, though the impact at large x remains substantial for the up-valence density in particular. For the nuclear case, the baseline is taken to be the EPPS16 PDFs. The simulated ATHENA data result in substantial improvements throughout the accessible EIC kinematic range for all quark flavours and also for the gluon density. The impact is particularly noteworthy at small x, where only very limited collider data (from the LHC) has previously been included. The sensitivity of the simulated low x data to log 1/x resummation effects is also evaluated.

Speaker: Paul Richard Newman (University of Birmingham (GB))

InclusivePDFs.v5.pdf

12:50 Probing the origin of nucleon spin with ECCE

One of the primary physics goals of the future electron-ion collider (EIC) is understanding the origin of nucleon spin from measurements of polarized DIS and SIDIS. Current analyses suggest that approximately 40% of nucleon spin is carried by gluon spin, and 30% each carried by quark spin and orbital angular momentum. However, existing data only extends to $x \approx 0.01$, and model-dependent extrapolations to lower $x$ (where gluon contributions dominate) result in large uncertainties. The kinematic reach of the EIC will provide significant constraints up to two orders of magnitude lower in $x$ than existing measurements. The proposed EIC Comprehensive Chromodynamics Experiment (ECCE) detector, centered on the existing BaBar 1.4 Tesla superconducting solenoid, has demonstrated the ability to perform measurements of key observables relevant to nucleon spin. This talk will give an overview of measurements sensitive to quark and gluon spin to be carried out by ECCE, and the expected impact of this data on our theoretical understanding of the origin of nucleon spin.

Speaker: Tyler Kutz

ecce_nucleon_spin_DIS2022.pdf

13:10 CORE - a Compact Detector for the Electron-Ion Collider

The COmpact detectoR for the Eic (CORE) concept has been envisioned in response to the “Call for Collaboration Proposals for Detectors to be located at the Electron-Ion Collider (EIC)”. The CORE detector is designed to satisfy the “mission need” statement with a physics scope that completely and comprehensively covers the one outlined in the EIC Community White Paper and the National Academies of Science (NAS) 2018 report. The distinguishing theme of the CORE detector is that it exploits fully technological advances in detector precision and granularity to minimize the overall size of the detector. CORE is a hermetic, high-luminosity, general-purpose detector designed to support the full EIC physics program, and as such could be used as a basis for either Detector 1 or 2 in IP6 or IP8. It is constructed around a short 3 T central solenoid. The tracking technology is essentially all silicon, and the electromagnetic calorimetry is based on the highest performance crystals available. Hadronic particle identification (PID) is achieved with a combination of compact gaseous and solid radiator ring-imaging Cherenkov detectors. The central detector is complemented by an extended suite of forward detectors downstream on the hadronic side of the intersection region. In this contribution, an overview of the detector is given complemented with simulated physics performances for a selection of physics channels.

Speaker: Gunar Schnell

DIS2022_Gunar.Schnell.pdf

13:30 → 15:00 Lunch

15:00 → 22:00 Free afternoon

Friday 6 May

09:00 → 10:55 Plenary sessions: Plenary 5

Convener: Halina Abramowicz (Tel Aviv University (IL))

09:00 Prospects for QCD, EW and Top Physics at the (HL-)LHC

Speaker: Robert Schoefbeck (Austrian Academy of Sciences (AT))

22-05-06 Prospects for QCD, EW and Top Physics at the (HL-)LHC.pdf

09:30 Prospects for Higgs Physics at the (HL-)LHC

Speaker: Elisabeth Petit (CPPM-Marseille (FR))

HiggsPhysicsDIS2022_ElisabethPetit.pdf

10:00 Experimental synergies between DIS and the LHC

Speaker: Monica D'Onofrio (University of Liverpool (GB))

DIS2022_Synergies_eh_hh_DONOFRIO.pdf

10:30 Summary of WG1

Speakers: Barak Schmookler (Stony Brook University), Thomas Cridge (University College London)

DIS2022_Summary_WG1_TomBarak.pdf

10:55 → 11:25 Coffee break

11:25 → 13:30 Plenary sessions: Plenary 6

Convener: Robert Samuel Thorne (University College London (UK))

11:25 Summary of WG2

Speakers: Daria Sokhan (CEA Saclay / Glasgow U.), Guillaume Beuf

Beuf_WG2_Theory_Summary_DIS2022v2.pdf

WG2_Summary_Exp_DariaSokhan.pdf

11:50 Summary of WG3

Speaker: Heidi Angelika Rzehak

DIS2022.pdf

12:15 Summary of WG4

Speakers: Maria Vittoria Garzelli, Xuan Li (Los Alamos National Laboratory)

DIS2022_WG4_experiment_summary_v2.pdf

DIS2022_WG4_template.pdf

12:40 Summary of WG5

Speaker: Pasquale Di Nezza (INFN e Laboratori Nazionali di Frascati (IT))

Summary WG5 - Di Nezza.pdf

13:05 Summary of WG6

Speaker: Michela Chiosso (University of Torino and INFN)

DIS2022_summary_talk_WG6_2.pdf

13:30 → 15:00 Lunch break

15:00 → 17:15 Plenary sessions: Plenary 7

Convener: Nestor Armesto Perez (Universidade de Santiago de Compostela (ES))

15:00 Guido Altarelli Award 2022

Speaker: Elisabetta Gallo (DESY)

220506_DIS2022_AdiAshkenazi.pdf

Talk1_Award_2022_Presentation.pdf

Talk3_DIS2022_Mistlberger.pdf

15:35 DIS in the big picture of HEP

Speaker: Fabrizio Caola (University of Oxford (GB))

DIS22_caola.pdf

16:10 Future of DIS

Speaker: Jorgen D'Hondt (Vrije Universiteit Brussel (BE))

DIS-future-JorgenDHondt-May2022-final.pdf

16:45 Presentation by the IAC

Speaker: Paul Richard Newman (University of Birmingham (GB))

IAC-report-2022-v2.pdf

17:05 Farewell

Speaker: Nestor Armesto Perez (Universidade de Santiago de Compostela (ES))

Farewell_060522.pdf