virtual Quarkonia As Tools 2021

22 Mar 2021, 09:00 → 26 Mar 2021, 19:00 Europe/Brussels

Virtual

Jean-Philippe Lansberg (Centre National de la Recherche Scientifique (FR))

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Note: registration is mandatory to receive the zoom link to connect to the sessions.

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A first version of the timetable is now out. Although it is subject to small changes, all the speakers are invited to check that the assigned date and time for their talk is suitable.

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The workshop will be a virtual edition of a new series of meetings focused on the experimental and theoretical studies of quarkonia as tools to explore the structure of nucleons and nuclei, the phase diagram of QCD, the spin content of the nucleons, the coupling of the Higgs boson to heavy quarks, ...

Each day will be dedicated to specific systems and observables: collisions involving protons, mesons and leptons, proton-nucleus collisions, heavy-ion collisions, polarised nucleons and spin observables, and exclusive reactions including the ultra-peripheral hadron collisions. From the first two editions emanated a review on the opportunities for quarkonium production at the HL-LHC: http://arxiv.org/pdf/2012.14161.pdf

This year, the workshop will take place the week after the Quarkonium Working Group (QWG) workshop to be held remotely. We encourage the participants to assist to the QWG workshop, in particular to the production sessions.

Given the sanitary context, it is very complicated for our young colleagues to advertise their work. As such, they will benefit from full priority to give talks. The tradition of the workshop is to ask as much as possible to the speakers to enlarge the scope of their talks. We stick to this tradition and invite PhD and Postdocs to submit an abstract as an expression of their interest to speak on specific topic of the workshop.

We will have two sessions of 2 hours daily, which will hopefully allow our colleagues from Asia and America to actively contribute. At least half of the afternoon sessions will be dedicated to talke related to the US EIC.

Topics (tentative):

• Monday: Inclusive reactions (incl. jets & isolation) & tools for PDFs
• Tuesday: Exclusive reactions & tools for GPDs & Wigner functions,...
• Wednesday: Reactions with polarisation & tools for TMD functions, spin asymmetries,...
• Thursday: Reactions with nuclei & tools for nuclear PDFs, Cold Nuclear Matter,...
• Friday: Reactions with 2 nuclei & tools for Quark-Gluon Plasma,Multi-particle interactions, ...

Conveners:

D. Boer, E. Chapon, B. Ducloué, M.G. Echevarria, P.B. Gossiaux, V. Kartvelishvili, T. Kasemets, D. Kikola, R. McNulty, D. Price, H.S. Shao, C. Van Hulse, M. Winn

Acknowledgements:

This scientific event is supported by the CNRS-IN2P3 (TMD@NLO, LIA FCPPL, PICS Excitonium), The French ANR, the GDR QCD and the Labex P2IO.

Previous workshops:
Quarkonia As Tools 2019, January 13-19 2019, Aussois (France)

Quarkonia As Tools 2020, January 12-18 2020, Aussois (France)

 

  

vQaT21_Zoom_Wonder.pdf

Monday, 22 March

Day 1 (mostly inclusive reactions): Morning session

Convener: Darren Price (University of Manchester (GB))

09:45 Virtual Coffee break on Wonder

1 Intro

2 Study of charmonium production with the LHCb

This contribution is devoted to understanding charmonium production mechanism using data from the LHCb experiment. It also suggests an exploration of new observables and proposes a series of new approaches on charmonia studies in LHCb. It will describe a possible extension of a series of breakthrough studies, performed at IJCLab (former LAL) and UCAS within the LHCb collaboration and documented in Refs. [1, 2, 3, 4].

The most precise charmonium studies employ decays into experimentally clean dimuon final state, which is possible for $J^{PC}=1^{- -}$ charmonia, such as $J/\psi$ and $\psi (2S)$ states. In addition, $\chi_{cJ}$ states can be reconstructed via their radiative decays to $J/\psi$, which, however, requires a reconstruction of a low-energy photon. Other charmonium states are accessible via hadronic decays. Therefore the decays to such final states as $p\bar{p}$, $\phi\phi$, $\Lambda \bar{\Lambda}$ allow to study simultaneously multiple charmonium states. The LHCb experiment is well positioned for these studies due to its precise vertex reconstruction, momentum measurements, and powerful particle-identification performance, which allows suppressing high combinatorial background.

The next-to-leading order (NLO) calculations in NRQCD successfully describe the measurements of $J/\psi$ and $\psi (2S)$ production rates in, however, a limited range of transverse momentum. While NRQCD provides a good description of the $J/\psi$ production and polarization, a consistent description of the $J/\psi$ production and polarization together with the production of the $\eta_c(1S)$, described by linked long-distance matrix elements (LDMEs), remains challenging [5]. This judgment is based on a factorization approach and linking of the LDMEs corresponding to the $J/\psi$ and $\eta_c(1S)$ production within a heavy-quark spin symmetry assumption. The first $\eta_c(1S)$ production measurement by LHCb [2] triggered a major revisiting of the theoretical framework and yielded new approaches capable to describe simultaneously the three observables, however, in a limited $p_T$ range.
The recent $\eta_c(1S)$ production measurement [4] further constrains the theory and indicates another fundamental consistency problem to be solved in the coming years. Meanwhile, J.-P. Lansberg, H.-S. Shao and H.-F. Zhang outlined that the studies of the first excited state of $\eta_c(1S)$, the \eta_c(2S) meson, will allow clear and unambiguous interpretation and estimated the expected $\eta_c$ meson hadroproduction cross-section in the LHCb acceptance at 13 TeV [6]. Theory suggests the same relations between parameters for $\eta_c(2S)$ and $\psi(2S)$ states, as for $\eta_c$ and $J/\psi$. Moreover, a pair of excited states is expected to be free from feed-down contributions. Therefore, a measurement of their production cross section will provide a possibility to further test main NRQCD assumptions. Further lacking important measurements of charmonia hadroproduction are those for $h_c$ and $\chi_{cJ}$ states. Using a dedicated 2D fit technique and reconstructing charmonia via their decays to two phi mesons, LHCb measured [3] the branching fractions of $b$-hadron inclusive decays to the $\chi_{cJ}$ states providing first or most precise results.

A new technique has recently been proposed to constrain theory using results of both charmonia hadroproduction and charmonia production in $b$-hadron inclusive decays under the assumptions of factorization, LDME universality, and heavy-quark spin symmetry, where different charmonium states are involved. Using the LHCb measurements, this technique allowed a first direct comparison between the LDMEs, responsible for the $J/\psi$ and $\eta_c(1S)$ hadronization, as determined from hadroproduction and from $b$-hadron decays. In addition, it allowed to strongly constrain the corresponding matrix elements and revealed a clear problem in theory description of $b$-hadron inclusive decays to the $\chi_{cJ}$ states. Alternatively, once hadroproduction and production in $b$-decays will be measured for charmonium states with linked LDMEs, the most basic theory assumptions can be tested quantitatively.

Speaker: Valeriia Zhovkovska (Université Paris-Saclay (FR))

Quarkonium_as_Tools.pdf

Zhovkovska.mp4

3 QCD corrections to pseudoscalar hadroproduction

Speaker: Melih Arslan Ozcelik (Université Paris-Saclay (FR))

Ozcelik.mp4

SlidesQAT2021_Ozcelik.pdf

4 Multiplicity depedence of quarkonium production

At the LHC collision energies, multiple parton interactions (MPI) are a key ingredient for particle production models including hard scale processes like heavy-quark production (charm and beauty). Multiplicity dependent quarkonium measurements can shed light on the role of MPI at such hard momentum scales, as well as on the interplay between hard and soft particle production mechanisms. Such studies can contribute to improve the understanding of the initial state of hadronic collisions as well as the emergence of collectivity with rising energy and collision system size. In addition, the various design and configurations of the LHC detectors, giving access to different measurement conditions and observables, provide a large set of complementary measurements necessary to study initial and final state effects. These final state effects include a potential dissociation of excited quarkonium states w.r.t. the ground state, investigated through multiplicity differential measurements. In this contribution, a review of the most recent results on multiplicity dependent quarkonium production will be presented. Ongoing studies and possibilities for future related measurements will also be discussed.

Speaker: Manuel Guittiere (Université Paris-Saclay (FR))

Guittiere.mp4

QaT21_MG.pdf

5 Heavy flavour at high energies: from open states to quarkonia

Speaker: Michael Fucilla (Università della Calabria)

Fucilla.mp4

Fucilla_Quarkonia_As_Tools (2021).pdf

6 Physics with charmonia at the SPD experiment

The SPD experiment is planned to operate at the second interaction point of the NICA facility, which is under construction at the JINR. The primary goal of the experiment is a comprehensive study of the polarized and unpolarized gluon structure of proton and deuteron in polarized $pp$, $dd$, and $pd$ collisions at $\sqrt{s}$ up to 27 GeV and luminosity up to $10^{32}$cm$^{-2}$s$^{-1}$. Several complementary experimental probes will be available: charmonia, open charm, and prompt photons. In this talk, the experiment will be briefly introduced and prospects of measurements with charmonia will be discussed.

Speaker: Igor Denisenko (Joint Institute for Nuclear Research (RU))

Denisenko.mp4

Denisenko_QaurkoniaAsTools2021v2.pdf

Day 1 (mostly inclusive reactions): Afternoon session (incl. EIC)

Convener: Huasheng Shao (Centre National de la Recherche Scientifique (FR))

15:45 Virtual Coffee break on Wonder

7 X(3872) production and suppression

I review the literature on charmonium suppression in hadronic collisions, and why understanding the source of the suppressions observed are important.
I highlight models that have failed and succeeded at explaining this suppression, and what physics these models adopt to account for the suppressions.
Finally, I discuss a new model that is physically well motivated, and also applies to extended objects like the $X(3872)$.

Speaker: Kevin Ingles (Ohio State University)

X(3872)_production_and_suppression.pdf

8 Production and polarization of direct $J/\psi$ to ${\mathcal O}(\alpha_s^3)$ in the improved color evaporation model in collinear factorization

One of the best ways to understand hadronization in QCD is to study the production of quarkonium. The color evaporation model (CEM) and Nonrelativistic QCD (NRQCD) can describe production yields rather well but spin-related measurements like the polarization are stronger tests. In this talk, we will present the first calculation of quarkonium polarization in the improved color evaporation model (ICEM) by considering all diagrams at the order of 𝛼3𝑠 and integrating over all color states.

Speaker: Vincent Cheung (LLNL)

Cheung.mp4

CheungTools2021Slides.pdf

9 EIC Intro & Quarkonium production at threshold at the EIC

to come

Speaker: Sylvester Joosten (Argonne National Laboratory)

Joosten.mp4

QAT-EIC-and-threshold.pdf

10 Exploring $J/\psi$ production mechanism at the future Electron-Ion Collider

We propose to use transverse momentum $p_T$ distribution of $J/\psi$ production at the future Electron Ion Collider (EIC) to explore the production mechanism of heavy quarkonia in high energy collisions. We apply QCD and QED collinear factorization to the production of a $c\bar{c}$ pair at high $p_T$, and non-relativistic QCD factorization to the hadronization of the pair to a $J/\psi$. We evaluate $J/\psi$ $p_T$-distribution at both leading and next-to-leading order in strong coupling, and show that production rates for various color-spin channels of a $c\bar{c}$ pair in electron-hadron collisions are very different from that in hadron-hadron collisions, which provides a strong discriminative power to determine various transition rates for the pair to become a $J/\psi$. We predict that the $J/\psi$ produced in electron-hadron collisions is likely unpolarized, and the production is an ideal probe for gluon distribution of colliding hadron (or nucleus). We find that the $J\psi$ production is dominated by the color-octet channel, providing an excellent probe to explore the gluon medium in large nuclei at the EIC.

Speaker: XIANGPENG WANG (Argonne National Laboratory)

Wang.mp4

Xiangpeng_Wang.pdf

11 Large-P_T inclusive photoproduction of J/ψ in electron-proton collisions at HERA and the EIC

We study the inclusive J/ψ production at large transverse momenta at lepton-hadron colliders in the limit when the exchange photon is quasi real, also referred to as photoproduction. Our computation includes the leading- PT leading- v next-to-leading αs corrections. In particular, we consider the contribution from J/ψ plus another charm quark, by employing for the first time in quarkonium photoproduction the variable-flavour-number scheme. We also include a QED-induced contribution via an off-shell photon which remained ignored in the literature and which we show to be the leading contribution at high PT within the reach of the EIC. In turn, we use our computation of J/ψ+charm to demonstrate its observability at the future EIC and the EIC sensitivity to probe the non-perturbative charm content of the proton at high x .

Speaker: Yelyzaveta Yedelkina (Paris-Saclay University)

EIC-onium-220321-YY.pdf

Yedelkina.mp4

Tuesday, 23 March

Day 2 (mostly exclusive reactions): Morning session

Convener: Ronan Mcnulty (University College Dublin (IE))

09:45 Virtual Coffee break on Wonder

12 Intro

13 UPC measurements with ALICE

While HERA taught us that the proton is mainly occupied by gluons for Bjorken x < 10⁻², the LHC
gives the possibility to measure the gluonic structure of the proton and nuclei at Bjorken x ∼ 10⁻⁵.

Measurements of photon-induced reactions in ultra-peripheral collisions (UPCs) of Pb-Pb and p-Pb nuclei at the LHC have been performed with ALICE in the past years. In these reactions, the photon coming from the Pb nucleus is used as a probe to unveil information on parton distributions in the target (proton or Pb nucleus). While Pb-Pb UPCs are a tool to study shadowing at various centre- of-mass energies - hence various Bjorken-x scales - p-Pb UPCs may give hints on the saturation of gluons in the proton, as predicted by the color glass condensate effective field theory. Indeed, whereas the BFKL as well as DGLAP equations are linear and only include parton splitting, non- linear effects (BK/JMWLK evolution) may interfere at very low x.

In 2013, a measurement has been performed down to x ∼ 3 × 10⁻⁵, corresponding to a factor of
two larger than the highest energy studied at HERA. No significant change in the gluon density
behaviour of the proton between HERA and LHC energies was found. The data of p-Pb UPCs
taken by the ALICE collaboration in 2016 have an enhanced luminosity, and the center-of-mass
energy was increased by another factor 2: it should now be possible to reveal new constraints on the gluonic structure of the proton down to x ∼ 8 × 10⁻⁶.

Speaker: Aude Glaenzer (Université Paris-Saclay (FR))

Glaenzer.mp4

quarkonia as tools.pdf

14 Central exclusive production of J/psi and psi(2S) mesons at LHCb

In quasi-elastic proton-proton collisions at the LHC, central exclusive production (CEP) of vector mesons can take place via the fusion of a photon and a pomeron (a colourless strongly-coupled object with the quantum numbers of the vacuum), while the protons remain intact. The central exclusive production of $J/\psi$ and $\psi$(2S) mesons provides clean events, which is uncommon at hadron colliders. This presentation shows results for CEP production of $J/\psi$ and $\psi$(2S) mesons at LHCb, both in $pp$ collisions at a centre of mass energy, $\sqrt{s}$, of 13 TeV and in PbPb collisions at $\sqrt{s_{NN}}=5$ TeV.

Speaker: Cristina Sánchez Gras (Nikhef National institute for subatomic physics (NL))

CSanchezGras-QuarkoniaAsTools-210323.pdf

Sanchez-Gras.mp4

15 Phenomenological assessment of proton mechanical properties

A unique feature of generalised parton distributions is their relation to the QCD energy-momentum tensor. In particular, they provide access to the distributions of pressure and shear stress induced by its quark and gluon structure. In principle the pressure distribution can be experimentally determined in a model-independent way from a dispersive analysis of deeply virtual Compton scattering data through the measurement of the subtraction constant. In practice the kinematic coverage and accuracy of existing experimental data make this endeavour a challenge even in the quark sector. Elaborating on recent global fits of deeply virtual Compton scattering measurements using artificial neural networks, we present the current knowledge on this subtraction constant. We also emphasize the interest of probing GPDs through the production of quarkonia to access the pressure distribution induced by gluons. This study will pave the way for future multi-channel analysis when more precise data will become available, eg obtained in the foreseen electron-ion colliders EIC and EIcC, or at the high
luminosity LHC.

Speaker: Hervé DUTRIEUX (CEA)

Dutrieux.mp4

DUTRIEUX_Quarkonia_as_tools.pdf

16 Diffractive quarkonium production with target break-up at an EIC

Diffractive events can be divided in two categories. First, in so called coherent diffraction the target remains on its ground state. In incoherent diffraction, on the other hand, the target breaks up, but the event is still diffractive, i.e. there is no net color charge transfer to the target. One advantage of diffractive processes is that the total momentum transfer can be measured by measuring the quarkonium transverse momentum. As the momentum transfer is Fourier conjugate to the impact parameter, diffractive processes enable studies of the spatial distribution of partons in the target hadrons. A second advantage is that at lowest order at least two gluons need to be exchanged in a diffractive event, which makes the cross section approximatively sensitive to the squared gluon distribution of the target and as such a powerful probe of the small-x dynamics.

In this talk, we focus on incoherent quarkonium production in deep inelastic scattering. We discuss how it is possible to study, not only the average, but also the event-by-event fluctuating spatial structure of protons and nuclei at high energy. We demonstrate how the HERA and LHC data point towards significant event-by-event fluctuations in the spatial structure of protons, and discuss some phenomenological implications of these findings. In addition to spatial structure, we also discuss how to access non-linear saturation dynamics in incoherent scattering, and how it is possible to determine centrality and study saturation effects in the densests parts of the heavy nuclei at an Electron-Ion Collider.

Speaker: Dr Heikki Mäntysaari (University of Jyväskylä)

Maentysaari.mp4

quarkonia_2021_mantysaari.pdf

17 Round table: inclusive reactions in UPC ?

inclusive_upc.pdf

Day 2 (mostly exclusive reactions): Afternoon session (incl. EIC)

Convener: Charlotte Van Hulse (University College Dublin (IE))

15:45 Virtual Coffee break on Wonder

18 Quarkonium production at GlueX

to come

Speaker: Lawrence Ng

Ng.mp4

Quarkonia.pdf

19 Study of Short-Range nuclear Correlations in light nuclei using BeAGLE event generator

Nuclear dynamics at short distances among nucleons is one of the most outstanding phenomena in nuclear physics. Understanding the role of QCD in generating nuclear forces is important for uncovering the underlying physics of Short-Range Correlations (SRCs). In recent years, SRCs has been observed from light to heavy nuclei using fixed target experiments at Jefferson lab via high energy electron-nucleus scattering. In this talk, I will talk about the opportunity of studying SRCs using light nuclei with collider experiments, e.g., the Electron-Ion Collider (EIC). The experimental technique of studying the light nuclei can be based on exclusive processes with tagging final-state particles, in order to fully control the initial state of the target wavefunction. In particular, incoherent diffractive production of $J/\psi$ particle off deuteron will be presented. In addition, the spectral function in light nuclei has been recently modeled in the BeAGLE event generator, where the decay kinematics of the light nuclei and their influence on the very forward detector design at the EIC will be discussed.

Speaker: Zhoudunming Tu (BNL)

talk_Tu.pdf

Tu.mp4

20 Accessing GTMDs through pair production of jets, Quarkonia and open heavy flavours

Generalized transverse momentum-dependent parton distribution functions (GTMD-PDFs) are the building blocks that encode the spatial and momentum distribution of quarks and gluons inside hadronic matter. In the forward region (small-x) of deeply inelastic scattering (DIS) experiments, various inclusive and exclusive multi-particle observables depend only on two types of GTMD-PDFs: the dipole gluon and the Weizsacker Williams type.

In this talk, I will briefly review a few promising observables that give access to these two types of distributions. I will focus on the measurement of azimuthal correlations in the production of forward dijets, quarkonia, and open heavy flavor at the future Electron-Ion Collider (EIC). The complementarity and the challenges of measuring these observables at the EIC will be discussed.
Finally, I will attempt to address some recent developments on the computation of these observables at higher-order loop.

Speaker: Farid Salazar (Stony Brook University)

Salazar.mp4

virtual_Quarkonia_tools_2021.pdf

21 Discusion on a add-on on quarkonia to the EIC YR

Wednesday, 24 March

Day 3 (mostly Spin/TMDs): Morning session

Convener: Dr Miguel Echevarria (University of Alcala)

09:45 Virtual Coffee break on Wonder

22 Intro

23 Quarkonium emissions as probes of the hadronic structure at small-x

Quarkonium emissions in forward as well as in central directions of rapidity are widely recognized as excellent channels to access the nucleon structure in the high-energy/small-$x$ regime. Here, several phenomenological analyses have been proposed so far, this allowing us to probe kinematic ranges in the intersection corners of different approaches. At large transverse momenta, a high-energy factorization (HEF) formula is established within the Balitsky-Fadin-Kuraev-Lipatov (BKFL) formalism, where the so-called unintegrated gluon distribution (UGD) drives the gluon evolution at small-$x$. Recent analyses on the diffractive electroproduction of $\rho$ mesons have corroborated the underlying assumption that the small-size dipole scattering mechanism is at work, thus validating the use of the HEF formalism. Nonetheless, a significant sensitivity of polarized cross sections to intermediate values of the meson transverse momenta, where, in the case of inclusive emissions, a description at the hand of the transverse-momentum dependent (TMD) factorization starts to be most appropriate framework, has been observed. Similar studies on emissions of quarkonium states, whose theoretical description at small-$x$ mainly relies on quark dipoles of larger size, would certainly help us to shed light on the interplay between HEF and TMD formalisms. Moreover, when the TMD approach is considered, quarkonium-production reactions probe the gluon TMD densities. More in particular, they represent a golden channel for the extraction of those gluon densities which are sensitive to the Weizsacker-Williams (WW) gauge link.
In this overview talk I propose to address all the considered points, showing how phenomenological analyses doable at new-generation colliding machines, as the EIC, the HL-LHC and NICA-SPD, can accelerate progress in our understanding of the hadronic structure at small-$x$ via quarkonium production. Ultimately, they trace the path toward the development of a unified formalism, where both the TMD and the BFKL evolution mechanisms are consistently integrated in the definition of small-$x$ gluon TMD distributions.

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

Celiberto.mp4

talk_QAT_2021_HASsx_Celiberto.pdf

24 Status of heavy-quarkonium photoproduction at NLO in High Energy Factorization

Status of Next-to-Leading order calculation of the High-Energy Factorization coefficient function for the inclusive heavy-quarkonium photoproduction will be presented. The one-loop correction to the leading-order process:
R(q1) + gamma(q) -> c\bar{c} [1S0^(8)],
where R-Reggeized gluon with four-momentum q1=x1P1+qT1, qT1.P1=0, will be discussed within an effective-action framework described in Ref.[1]. An important new ingredient of the calculation is the rapidity-divergent one-loop integral with massive internal line, which should be calculated. An important cross-check of factorization is possible with this process, since the known one-loop rapidity divergence should factorize-out, despite color-octet final-state.

The LL BFKL analysis of the energy-dependence of total cross-section of eta_c production can be also discussed in the talk.

References:
[1] M.A.Nefedov, Computing one-loop corrections to effective vertices with two scales in the EFT for Multi-Regge processes in QCD,
Nucl. Phys. B \textbf{946}, 114715 (2019)
doi:10.1016/j.nuclphysb.2019.114715
[arXiv:1902.11030 [hep-ph]].

Speaker: Dr Maxim Nefedov (Samara State University)

Nefedov.mp4

QaT-2021.pdf

25 TMD shape-functions in SIDIS from octet and singlet pairs

In this talk I will discuss the TMD factorization and shape functions for quarkonium production in direct photo and lepto-production. The leading power contribution from color octets yields a more familiar form for the factorized cross section involving the quarkonium TMD-shape functions. The singlet contribution, which can be enhanced due to relative velocity power-counting, involves subleading operators and results in an intriguing “factorized” expression.

Speaker: Yiannis Makris

Makris_2021.pdf

Makris.mp4

26 Round table: kT-dependence and quarkonium production

RoundTable.mp4

27 Problems, pitfalls and remedies of gluon TMD measurements

Based on generator-level simulations, a number of potential problems and pitfalls of the measurement of gluon TMD in the jpsi+gamma final state will be presented, and remedies suggested.

Speaker: David Hagan (Lancaster University (GB))

Hagan.mp4

ProblemspitfallsandremediesofgluonTMDmeasurementsQaT2021-03-24.pdf

Day 3 (mostly Spin/TMDs): Afternoon session (incl. EIC)

Convener: Daniel Boer

15:45 Virtual Coffee break on Wonder

28 Quarkonium spin asymmetry measurements in p+p collisions by the PHENIX Experiment at RHIC

Measurements of heavy quark bound states, like J/psi meson, provide a unique opportunity to study QCD properties. General features of quarkonia production such as cross-sections and transverse momentum distributions are well described by many existing models. In order to differentiate between various models one has to study quarkonia production in more details. One of the observables which can be used for this purpose is angular distribution of leptons produced in quarkonium decays, usually called polarization or spin asymmetry.
The PHENIX experiment at RHIC has measured inclusive J/psi polar and azimuthal angular decay coefficients at the mid (|y|<0.35) and forward (1.2<|y|<2.2) rapidity in p+p collisions at 200 GeV and 510 GeV. In this talk the analysis details as well as the results in different polarization frames will be presented and compared to theory.

Speaker: Alexandre Lebedev (Iowa State University (US))

A.Lebedev_virtualQaT_2021.pdf

Lebedev.mp4

29 SSAs in pp -> J/psi X: the gluon Sivers function and its process dependence

We study transverse Single-Spin Asymmetries (SSAs) for $J/\psi$ production in $p^↑ p→J/\psi+X$ within the phenomenological approaches of the Generalized Parton Model (GPM) and its extension, the Colour Gauge Invariant-GPM (CGI-GPM). Such SSAs are expected to give access to the so-called gluon Sivers function (GSF), a still poorly known transverse momentum dependent distribution (TMD). In both schemes, transverse momentum and spin effects are taken into account in the calculation of the asymmetries but, while in the GPM TMDs are considered to be universal, in the CGI-GPM the GSF becomes process dependent because of the additional inclusion of initial- and final-state interactions. Concerning quarkonium formation, we adopt both the Colour-Singlet Model (CSM) and the Non-Relativistic QCD (NRQCD) approach. We compare the results obtained by maximizing the GSF in the different frameworks with existing data from the PHENIX Collaboration at RHIC. Moreover, we provide corresponding estimates for future fixed-target experiments at the LHC.

Speaker: Luca Maxia (INFN - National Institute for Nuclear Physics)

Maxia.mp4

Quarkonia - TMDs CGI.pdf

30 Estimates for the transverse single-spin asymmetries in $p^{\uparrow}p \to J/\psi X$ process at PHENIX RHIC and SPD NICA

In our work we are interested in the transverse single-spin asymmetry (TSSA) of $p^{\uparrow}p\to J/\psi X$ process, incorporating both transverse-momentum and spin effects. To predict production cross section of prompt $J/\psi$ we use two different approaches, the nonrelativistic QCD (NRQCD) factorization approach and the Improved Color Evaporation Model (ICEM), and show how the predicted results for TSSAs depend on choice of a hadronization model. For unpolarized cross sections we compare LO predictions of different factorization models, namely the standard Generalized Parton Model (GPM), the Parton Reggeization Approach (PRA) and also the Collinear Parton Model (CPM) at NLO, with data of the PHENIX collaboration and between each other. Within a region of small transverse momenta all these models are in agreement. For the TSSA we consider two models of initial-state factorization: the GPM and its Colour-Gauge Invariant formulation (CGI-GPM). Estimates for the TSSAs in $p^{\uparrow}p \to J/\psi X$ process for the conditions of the future SPD NICA experiment are presented for the first time.

Speaker: Dr Anton Karpishkov (Samara National Research University and JINR)

Karpishkov.mp4

QaT2021_Karpishkov.pdf

31 Role of the gluon Sivers function in $l\,p^\uparrow \to l^\prime+J/\psi+ X$ at the EIC

We study the Sivers azimuthal asymmetry, and the role of the gluonSivers function (GSF), in inelastic $J/\psi$ leptoproduction, $l\,p^\uparrow\to l^\prime+J/\psi+ X$ within a phenomenological TMD scheme, known as the generalized parton model (GPM). We adopt the NRQCD effective theory for the quarkonium formation mechanism and employ the colour-gauge invariant version of the GPM to study the effects of final-state interactions on the GSF. We compare our results for the unpolarized cross sections against H1 and ZEUS data, and the maximized Sivers asymmetry with the available data point from the COMPASS Collaboration. We also present estimates for the maximized Sivers asymmetry at the EIC.

Speaker: Rajesh Sangem (INFN Cagliari & University of Cagliari)

Rajesh.mp4

Rajesh_Quarkonium_2021.pdf

32 Probing linearly polarized gluon distribution in $J/\psi$ electroproduction at electron-ion collider

We present a recent calculation of $cos2\phi$ asymmetry in $J/\psi$ production, in an unpolarized electron-proton collision, using non-relativistic QCD (NRQCD) based color octet model. This can probe the linearly polarized gluon distribution in the unpolarized proton within the kinematical range of the planned Electron-Ion Collider (EIC). We calculate the asymmetry in the kinematical region $z<1$, where the next-to-leading order (NLO), in $\alpha_s$, subprocess $\gamma*+g\rightarrow J/\psi+g$ gives the leading contribution. We present numerical estimates of the asymmetry using two different models for TMDs: (1) the Gaussian-type parameterization and (2) the McLerran-Venugopalan model at small $x$.

Speaker: Raj Kishore (IIT Bombay)

Kishore.mp4

QaT2021_rajkishore.pdf

33 Gluon TMDs and quarkonium production at the EIC

Transverse momentum dependent parton distribution functions (TMDs) are extensions of the well-known collinear PDFs. They contain, apart from the usual x- and scale dependence, also information on the intrinsic transverse momentum carried by the parton, and on the spin correlations.
Experimentally, not so much is known about gluon TMDs, since they are subleading with respect to their quark counterparts in the few processes for which TMD factorization is proven (Drell-Yan, SIDIS). This problem is bypassed by studying quarkonium, to which the gluon distributions in the proton couple already at leading order.
I will review two recent studies [1,2] where inclusive and associated quarkonium electroproduction is put forward as a probe of the proton gluon TMDs. I will then elaborate on subtleties [3] that arise, related to the transverse-momentum dependence of the so-called long distance matrix elements (LDMEs), which encode the nonperturbative information on the hadronization of the heavy-quark pair.

[1] A. Bacchetta, D. Boer, C. Pisano, and P. Taels, Gluon TMDs and NRQCD matrix elements in production at an EIC, Eur. Phys. J. C 80 (2020) 72
[2] U. D’Alesio, F. Murgia, C. Pisano, and P. Taels, Azimuthal asymmetries in semi-inclusive +jet production at an EIC, Phys. Rev. D 100 (2019) 094016
[3] D. Boer, U. D’Alesio, F. Murgia, C. Pisano, and P. Taels, meson production in SIDIS: matching high and low transverse momentum, JHEP 09 (2020) 40

Speaker: Pieter Taels (Ecole Polytechnique)

Taels.mp4

Virtual QaT 2021 - Pieter Taels.pdf

Thursday, 25 March

Day 4 (mostly proton-nucleus collisions): Morning session

Convener: Bertrand Ducloue (The University of Edinburgh)

09:45 Virtual Coffee break on Wonder

34 Intro

35 Quarkonium-physics case of the LHC in the fixed-target mode

I will review the possibility offered by the LHC beams in the fixed-target mode to advance our knowledge on quarkonium physics.

Speaker: Andrea Signori (University of Pavia and Jefferson Lab)

Signori.mp4

Signori_QaT.pdf

36 Fixed target physics at LHCb

The LHCb experiment has the unique capability to operate as both a collider experiment and a fixed-target experiment. This talk will discuss what was learned from the first phase of the fixed-target program at LHC and what can be expected from the upgraded system, which will begin providing high-statistics fixed target data when the LHC resumes operation.

Speaker: Saverio Mariani (Universita e INFN, Firenze (IT))

Mariani.mp4

Mariani_SMOG2@QuarkoniaAsTools_210325.pdf

37 J/psi pair production in pion-nucleon collisions at COMPASS

During the past 40 years, the production of pairs of the J/psi mesons in high energy hadron collisions has been studied by several experiments. Despite the experimental and theoretical efforts, the origin of the process and the relative weight of different production mechanisms still remain unknown. Depending on the energy scale the double J/psi production can be described by single- and double-parton scattering sub-processes and gluon-gluon fusion or quark-antiquark annihilation mechanisms. The process can also be related to the hypothesis of the intrinsic charm of hadrons and the existence of exotic tetraquark states which were predicted by various theoretical models and have recently been observed by the LHCb experiment.
To study dimuon reactions the COMPASS experiment at CERN uses a 190 GeV/c negative pion beam impinging on different nuclear targets. In this talk, the first preliminary COMPASS results on J/psi pair production will be presented. The search for possible signals from exotic resonances and the study of double J/\psi production mechanisms will be discussed.

Speaker: Andrei Gridin (Joint Institute for Nuclear Research (RU))

Gridin.mp4

Gridin_QAT.pdf

38 A technique for studying J/$\psi$-hadron interactions using femtoscopic correlations

Interactions with hadrons contribute to the suppression of quarkonium production observed in heavy-ion collisions. It is difficult to disentangle such cold nuclear matter effect from the effect of Debye-like screening of color charges in QGP, created in these collisions. Femtoscopic correlations of J/$\psi$-hadron allow to directly measure both elastic and inelastic scattering cross sections for these interactions.

We present a new method of estimating the J/$\psi$-h elastic and inelastic interaction cross sections using Lednicky-Lyuboshitz model in order to extract the strong interaction parameters. We also present feasibility studies for such measurement in LHCb and STAR experiments. These studies are already possible at LHCb and in the future, other LHC experiments as well.

Speaker: Dr Leszek Kosarzewski (Czech Technical University in Prague)

Jpsi-h_femto_LK_2021_3_25.pdf

Kosarzewski.mp4

Day 4 (mostly proton-nucleus collisions): Afternoon session (incl. EIC)

Convener: Daniel Kikola (Warsaw University of Technology (PL))

15:45 Virtual Coffee break on Wonder

39 Event activity dependence of heavy flavor and quarkonium production in small collision systems

Open heavy flavor and quarkonium are valuable probes to identify the underlying QCD dynamics behind high multiplicity events at RHIC and LHC. The origin of collective flow found in small collision systems ($p+p$ and $p+A$) is still under debate, but the initial state interaction (gluon saturation) could be a significant source, giving high charged multiplicity. Recent LHC data on the event activity dependence of quarkonium ($J/\psi$) yield in small systems have shown that the initial state saturation effect without final state flow effects can describe data quantitatively; this indicates that the initial state saturation effect would provide some constraints on other final state effects. In this talk, I will briefly discuss recent theoretical studies on quarkonium production in small systems in the CGC/small-x saturation framework, a useful tool to examine the QCD dynamics in high multiplicity events. I will also discuss open-heavy flavor ($D$) and its decay lepton ($c\to e,\mu$) production in small systems as a baseline against quarkonium production.

Speaker: Kazuhiro Watanabe (Subatech)

QAT21-Watanabe.pdf

Watanabe.mp4

40 Quarkonium production in proton-nucleus collisions at the LHC

The study of quarkonium production in proton-nucleus collisions has been widely explored by all LHC experiment and represents a valuable tool in the investigation of cold nuclear matter (CNM) effects in relativistic heavy-ion collisions. Mechanisms such as the modification of the parton distribution functions in nuclei, the presence of a color glass condensate or the coherent energy loss of the $q\bar{q}$ pair in the medium have been employed to describe J/$\psi$ and $\Upsilon(1\rm{S})$ production in proton-nucleus collisions. Moreover, final state mechanisms, possibly related to the presence of a dense medium, are required to explain the stronger suppression observed for more loosely bound quarkonium states (i.e. $\psi(2\rm{S})$). In addition to quarkonium production studies, p--Pb collisions provide a unique opportunity to explore collectivity in small systems, in particular through the measurement of the J/$\psi$ $v_{2}$, obtained using J/$\psi$-hadron correlations.\

In this presentation the most recent quarkonium measurements in proton-nucleus collisions obtained by the four LHC experiments will be discussed. The results will be given at mid (ALICE, CMS, ATLAS) and forward (ALICE, LHCb) rapidity and as a function of the transverse momentum, centrality and multiplicity.

Speaker: Luca Micheletti (Universita e INFN Torino (IT))

Micheletti.mp4

quarkonium_production_pA_Luca_Micheletti.pdf

41 Quarkonium measurements in small systems at LHCb

The LHCb collaboration has an unparalleled capability to reconstruct a wide range of conventional and exotic quarkonia states in small collision systems. We will discuss recent LHCb quarkonia results from high-multiplicity pp and pPb collisions, and what these probes teach us about the bound states of QCD, the effects of a nuclear medium, and the partonic structure of the nucleus

Speaker: Qiuchan Lu (South China Normal University (CN))

Lu.mp4

QuarkoniaAsTools_LHCb_QiuchanLu0325.pdf

42 Overview of DPS theory

Double parton scattering (DPS) is a nucleon-nucleon scattering where two partons from each nucleon undergo two independent hard scattering processes. It is usually suppressed with respect to the traditional single parton scattering (SPS). However, under some conditions (like for quarkonia production), DPS contributions can be comparable or even dominate with respect to the SPS. The study of DPS can also give insight into the 3D structure of nucleons.
In this talk we review the current status of the theoretical description of DPS in perturbative QCD. We focus on the DPS cross section formula and its factorization, and on the double parton distributions (DPDs), which are the DPS analog of PDFs.

Speaker: Riccardo Nagar (University of Milan Bicocca – INFN)

Nagar_DPS.pdf

Nagar.mp4

43 Transverse proton structure via double parton scattering in photon-induced interactions

In this contribution, we discuss the possibilities and advantages of observing double parton scattering (DPS) in photon-proton interactions. In general, DPS measurements give access to double parton distribution functions of the protons. These distributions represent a novel and promising tool, to access the 3D partonic structure of the proton, complementary to TMDs and GPDs. In fact, dPDFs encode double parton correlations in hadrons which cannot be accessed through, e.g., GPDs. Up to date, however, dPDFs are almost unknown, in particular, their dependence on the transverse distance of partons which is critical in DPS estimates.

In our previous analyses we discussed the impact of both perturbative and non perturbative double parton correlations in dPDFs. In addition, our collaboration also investigated how these effects affect an experimental observable called effective cross section, $\sigma_{eff}$. However, in proton-proton collisions, the information on the partonic proton structure are quite limited due to the lack of information on dPDFs and their relative first moment called effective form factor (eff), the latter entering the definition of $\sigma_{eff}$.

Therefore we propose to look for DPS in processes initiated by quasireal photon. In such photoproduction processes, the offshellness of the photons is controlled by measuring leptons, proton, or ions from the impinging beam scattered at low angle. At such low virtualities, the photon will fluctuate hadronically or electromagnetically in a $q\bar q$ pair which will then initiate a double parton scattering interacting on the proton.

The key idea is that measuring the virtuality of the quasi real photon
one is effectively controlling its transverse size and therefore appreciate
its interaction rate in the DPS mechanism offering information on the transverse
proton structure. In our analysis we prove that the dependence of
$\sigma_{eff}^{\gamma p}$ on the photon virtuality $Q^2$ could be quasi-directly
related to the mean transverse distance between two partons in the proton active
in the DPS process. Moreover, different models of the photon and proton effs
have been used to calculate, for the first time, $\sigma_{eff}^{\gamma p}(Q^2)$.

These results have been then used to estimate the DPS cross section for the
four jets production via DPS in HERA kinematics, since in this channel
collaborations reported significant MPI effects on the four jets cross section,
and exposed in their analyses possible contamination of the DPS processes.
By estimating the expected number of events
at integrated luminosity within reach at future facilities,
we conclude that DPS processes in photoproduction
gives a significant fraction of the four jet production cross sections,
if cuts on transverse momenta of the jets are low enough.
Moreover, the DPS peculiar dependence on $Q^2$ could be tested against models
of the photon and proton transverse structure, with the possibility to consider
even more exotic final states, involving, for example, single or double quarkonia.

Speaker: Matteo Rinaldi (Perugia University and INFN, Perugia)

Rinaldi.mp4

rinaldi.pdf

44 Investigations of coherent $J/\psi$ production background and eA collision geometry using forward particles at the EIC

The Electron Ion collider (EIC) is a next generation accelerator which will provide answers to burning questions in the field of nuclear physics. The EIC is a very versatile collider with a wide range of beam energies, polarizations, and species, as well as high luminosity, all required to precisely image quarks and gluons in spatial and momentum space and their interactions, to explore the new QCD frontier of strong color fields in nuclei – to understand how matter at its most fundamental level is made. One of the golden measurements at the EIC is coherent $J/\psi$ vector meson production in electron-nucleus (eA) scattering in order to obtain the spatial gluon density distribution in heavy nuclei. However, the background contamination from the incoherent process could be overwhelming; therefore, the background suppression in the experiment will be key for a successful measurement. We investigate the rejection of incoherent $J/\psi$ production by vetoing the nuclear breakup – through the decay protons, neutrons, and photons. A realistic estimate of the rejection power has been made based on the conceptual design of the interaction region and its detector acceptances and performances. Based on the same detector configurations, we also revisit the concept of defining the collision geometry in eA using forward produced neutrons. The study is based on the BeAGLE event generator, which is a hybrid model combining Pythia 6, DPMJet, and Fluka for simulating deep-inelastic scattering in electron-ion collisions. In addition studies comparing BeAGLE to existing ZEUS and E665 experimental data are also presented.

Speaker: Wan Chang (Institute of Particle Physics, Central China Normal University; Department of Physics, Brookhaven National Laboratory)

Chang.mp4

Tool 2021_WanChang.pdf

Friday, 26 March

Day 5 (mostky HIC, nPDFs & tools): Morning session

Convener: Émilien Chapon (Chinese Academy of Sciences (CN))

09:45 Virtual Coffee break on Wonder

45 Intro

46 Experimental review of bottomonium production in heavy-ion collisions at LHC

The primary subject in the research of high-energy heavy-ion collisions is to understand the nuclear matter produced in these interactions.
Bottomonia have been considered as golden probes to study the properties of such matter, as they are produced at early stages of collisions via hard-scattering processes. Also, their spectral functions are modified by Debye screening and interactions with partons inside the medium, suggesting sequential suppression of bottomonium states in heavy-ion collisions compared to the production in proton-proton (pp) collisions. This remarkable signature was first observed in lead-lead (PbPb) collisions at a nucleon-nucleon (NN) center-of-mass energy \sqrt{s_{NN}} = 2.76 TeV using the CMS detector at the CERN LHC. Bottomonium production in small collision systems e.g. pp or pPb collisions, has also been a subject with intensive interest, such as studying the initial state "cold nuclear matter (CNM)" effect and collectivity in high-multiplicity events.
This talk reviews and discuss the results of the bottomonium measurements at the CERN LHC reported by ALICE, ATLAS, CMS, and LHCb Collaborations in different collision systems.

Speaker: Jaebeom Park (Korea University (KR))

Park.mp4

QAT_210326_v1.pdf

47 Open quantum systems for quarkonium dynamics

In recent years, a lot of work has been done towards a dynamical description of quarkonia inside the QGP, using the open quantum systems formalism. In this framework, one can get a real-time description of a quantum system (here the quarkonium) in interaction with a thermal bath (the QGP) by studying the system reduced density matrix.

The first part of the talk will be devoted to a review of the use of open quantum systems to describe the evolution of heavy quarkonia in the QGP.

In the second part, I will investigate the real-time dynamics of a correlated heavy quark-antiquark pair inside the QGP using a quantum master equation previously derived from first QCD principles in [1]. The novel feature of our approach is to numerically solve the full equation, avoiding to perform semi-classical approximations as was done in [1] to solve them. The resolution is performed in 1D to lessen the computational cost, nonetheless it is sufficient to gain insight on the dynamics.

[1]-J. P. Blaizot and M. A. Escobedo, Quantum and classical dynamics of heavy quarks in a quark-gluon plasma, J. High Energy Phys. 06 (2018) 034.

Speaker: Stéphane Delorme (Subatech)

Delorme.mp4

Talk_QAT2021.pdf

48 Medium evolution of quarkonium within the EFT framework.

Quarkonium suppression is one of the probes of the formation of a quark-gluon plasma in heavy-ion collisions. Three phenomena influence the evolution of quarkonium in a medium: screening, collisions with medium partons and recombination. A formalism in which all these mechanisms can be described consistently is that of open quantum system. In this talk, I will review how to combine the open quantum system framework with Effective Field Theories that exploit the non-relativistic nature of quarkonium. I will discuss how to obtain a Lindblad equation that describes the evolution of the reduced density matrix of quarkonium and how Lattice QCD data can help to constraint the parameters of this equation. Efficient numerical methods to solve this evolution for phenomenological purposes will also be discussed.

Speaker: Miguel Ángel Escobedo Espinosa (Instituto Galego de Física de Altas Enerxías)

Escobedo.mp4

Qastools2021.pdf

49 Investigating the J/Psi flow

The quark-gluon plasma (QGP) is a strongly-interacting deconfined state of matter produced in ultra-relativistic heavy-ion collisions. In order to study the QCD matter phase of its evolution, quarkonia, bound states of a heavy quark and antiquark pair, are preferred tools as they are sensitive to the first stages of the collision and to the evolution of the created system.

Measurements of the azimuthal anisotropies (expressed as elliptic and triangular flows, $v_2$ and $v_3$ respectively) shed a light on collective behaviors of the particles within this hot and dense medium. For the $J/\psi$, the regeneration of charm quarks and geometrical anisotropies typically result in a non-zero $v_2$ while fluctuations in the medium are related to the $v_3$.
Measuring the azimuthal anisotropies of these hard probes gives us information regarding their own production mechanisms, and the formation of the QGP.

In this contribution, I review the results regarding the $J/\psi$ flow, from the first measurements at RHIC in Au-Au collisions at $\sqrt{s_{NN}}=200$ GeV, to the most recent ones provided by the LHC collaborations. Part of the measurements concern Pb-Pb collisions (up to $\sqrt{s_{NN}}=5.02$ TeV) in which the $J/\psi$ exhibits a significant non-zero $v_2$ in a wide centrality and $p_T$ range as well as a significant non-zero $v_3$. Other measurements focus on smaller systems like p-Pb. The p-Pb system, which is typically used as a standard candle for CNM effects in Pb-Pb, does display a non-zero $v_2$ for $3 < p_T < 6$ GeV/c whose magnitude is even comparable to the one from Pb-Pb collisions. The smallest hadronic system p-p is also being investigated. Proof of the $J/\psi$ flow in p-p would make a compelling case for collectivity in small systems.

Speaker: Sebastien Perrin (Université Paris-Saclay (FR))

Perrin.mp4

SPerrin_AsTools_2603.pdf

50 Chromoelectric Distribution Function of Nuclear Matter Probed by Quarkonium

Quarkonium suppression in heavy ion collisions has been used as a probe of the quark-gluon plasma (QGP) for decades. The intuitive picture of sequential suppression based on the Debye screening of the heavy quark potential is obscured by other in-medium processes such as dissociation and recombination. A natural question to ask is what we can learn about the QGP from measurements of quarkonium suppression.

In this talk, we will try to address this question using effective field theory techniques and the open quantum system formalism. We argue that when the quarkonium size is small, the interaction between quarkonium and the hot medium is weak. Then the density matrix of the heavy quark pair, as a subsystem, and the hot nuclear environment can be factorized. The time evolution of the subsystem is governed by the Lindblad equation. By applying the Wigner transform to the Lindblad equation and carrying out a gradient expansion, we derive the semiclassical Boltzmann equation and work out the leading quantum correction. The reaction rates are factorized into a quarkonium dipole transition function and a chromoelectric distribution function of the nuclear medium. For differential reaction rates, the chromoelectric distribution function is momentum dependent, defined by two electric fields connected via a staple-shaped Wilson line. For inclusive reaction rates, it becomes momentum independent and the Wilson line collapses into a straight line along the time axis. The relation between the Wilson line structures in the differential and inclusive reaction rates is similar to that between the gluon PDF and the gluon TMDPDF, except that the time here is the real time rather than the lightcone time. The construction can be easily generalized to the interaction between quarkonium and cold nuclear matter, which is of much relevance for quarkonium production in eA collisions, to be carried out in the future Electron Ion Collider.

Speaker: Dr Xiaojun Yao (Massachusetts Institute of Technology)

quarkonium.pdf

Yao.mp4

Day 5 (mostky HIC, nPDFs & tools): Afternoon session

Convener: Tomas Kasemets (JGU Mainz)

15:45 Virtual Coffee break on Wonder

51 FeynOnium

Speaker: Vladyslav Shtabovenko (KIT)

Shtabovenko-feynonium.pdf

Shtabovenko.mp4

52 NLOAccess: status and updates

We will review the status of the NLOAccess Virtual Access.

Speaker: Dr Carlo Flore (IJCLab Orsay, Paris-Saclay U. / IN2P3-CNRS)

Flore.mp4

talk-QaT-2021.pdf

53 nCTEQ Nuclear Parton Distribution Functions

Speaker: Khoirul Faiq Muzakka (University of Muenster)

Muzakka.mp4

slides.pdf

54 Towards nNNPDF3.0: A global analysis of nuclear parton distributions at NNLO and the impact of the Electron Ion Collider

Speaker: Rabah Abdul Khalek (Nikhef)

260321-Quarkonia.pdf

AbdulKhalek.mp4

55 Adjourn and discussion on June meeting