The Guido Altarelli Award honors the memory of the late Guido Altarelli, one of the founding fathers of QCD, an outstanding communicator of particle physics, and a mentor and strong supporter of Junior Scientists.
The top-quark pair production in association with heavy-flavour jets (b/c) is a difficult process to calculate and model and is one of the leading sources of background to ttH and 4tops in 1l/2LOS channel. To improve our understanding of this process, a new inclusive and differential measurement of this process was performed.
While the on-going Run-3 data-taking campaign will provide twice the integrated proton-proton luminosity currently available at the LHC, most of the data expected for the full LHC physics program will only be delivered during the HL-LHC phase. For this, the LHC will undergo an ambitious upgrade program to be able to deliver an instantaneous luminosity of $7.5\times 10^{34}$ cm$^{-2}$...
COMPASS is currently the longest-running experiment at CERN, having collected physics data for a record-breaking 20 years from 2002 to 2022. The experiment has a unique and diverse physics program focused on nucleon structure and spectroscopy measurements.
The experimental results obtained by COMPASS during its two phases (2002-2011 and 2012-2022, respectively) for a wide range of quark...
In this talk, I will show how ambiguities related to solutions of renormalisation group equations (RGEs) can contribute significantly to systematic uncertainties of theoretical predictions for physical observables. I will discuss a general method to estimate these systematic effects using techniques inspired by soft-gluon and transverse-momentum resummation approaches. As application cases, I...
The azimuthal correlation angle, $\Delta\phi$, between the scattered lepton and the leading jet in deep inelastic $e^{\pm}p$ scattering at HERA has been studied using data collected with the ZEUS detector at a centre-of-mass energy of $\sqrt{s} = 318 \;\mathrm{GeV}$, corresponding to an integrated luminosity of $326 \;\mathrm{pb}^{-1}$.
A measurement of jet cross sections in the laboratory...
A key open question in the study of multi-particle production in high-energy collisions is the relationship between the ``ridge'' - observed azimuthal correlations between particles in the underlying event that extend over all rapidities and hard or semi-hard scattering processes. In particular, it is not known whether jets or their soft fragments are correlated with particles in the...
Many-parameter fits to precise measurements in the framework of the Standard Model Effective Field Theory are becoming a standard interpretation of LHC and other collider data. In this contribution an overview is given of state-of-the-art EFT interpretations in ATLAS with particular emphasis on results in the top quark sector.
The LHC generates a beam of high-energy neutrinos in the forward direction, whose scientific potential has been ignored in the past. The FASERv and SND@LHC experiments have recently measured signals from these LHC neutrinos for the first time. To produce accurate predictions including NLO QCD corrections for FASER$\nu$ and SND@LHC and the planned experiments at the proposed Forward Physics...
Semi-inclusive hadron production in deep-inelastic lepton-nucleon scattering (SIDIS) is an important probe of the quark flavor structure of the nucleon and of the fragmentation dynamics of quarks into hadrons. In case of longitudinally polarized beams, SIDIS is a powerful tool for resolving the quark flavor decomposition of the proton’s spin structure. I report on the recent calculation of the...
Physicists anticipate that new physics phenomena will be discovered and/or confirmed during the High Luminosity Large Hadron Collider (HL-LHC) program. The primary argument is that the instantaneous luminosity will increase to 5-7.5 x 10^34 cm-2 s-1, approximately ten times the expected integrated luminosity of the LHC. This high-rate environment presents new challenges for the muon system of...
Approximately fifty years ago, the polarization of $\Lambda$ hyperons produced in unpolarized proton-beryllium collisions was discovered, though the origin of this phenomenon remains elusive. Many studies indicate that final-state effects, particularly from hadronization, play a significant role. Recently, it has been proposed that spin correlations of $\Lambda$ hyperons could provide insight...
Many models of physics beyond the Standard Model (SM) contain enhanced couplings to massive standard model particles like the W,Z,Higgs, and top. We present highlights of searches for new physics beyond the SM in final states containing these heavy particles, using proton-proton collision data collected with the CMS detector at the CERN LHC. The models probed can contain heavy gauge or higgs...
The muon spectrometer of the ATLAS detector will undergo a substantial upgrade during the Phase-II upgrade in Long Shutdown 3 to meet the operational demands of the High- Luminosity LHC. Most of the electronics for the Monitored Drift Tube (MDT) chambers, Resistive Plate Chambers (RPC), and Thin Gap Chambers (TGC) will be replaced to ensure compatibility with the higher trigger rates and...
We present an update to our SIDIS-based approach for dimuon production in neutrino-nucleus collisions [1]. Dimuon production, an important constraint for the strange-quark distribution in global analyses of both proton and nuclear parton distributions, has traditionally been calculated by assuming factorization to the inclusive DIS charm production process. In our approach, we forego this...
In deep-inelastic positron-proton scattering, the lepton-jet azimuthal angular asymmetry is measured using data collected with the H1 detector at HERA. When the average transverse momentum of the lepton-jet system, $\lvert \vec{P}_\perp \rvert $, is much larger than the total transverse momentum of the system, $\lvert \vec{q}_\perp \rvert$, the asymmetry between parallel and antiparallel...
We present NNPDFpol2.0, a new set of polarised parton distribution functions (PDFs) of the proton based on legacy measurements of structure functions in inclusive polarised deep-inelastic scattering (DIS), and of W-boson, single-inclusive, and di-jet production asymmetries in polarised proton-proton collisions. The determination is accurate to next-to-next-to-leading order in the strong...
We provide an update on QCD predictions for top-quark pair production close to threshold including bound state effects at the Large Hadron Collider (LHC) [arXiv:2412.16685]. We compute the top-quark pair invariant mass distribution, including Coulomb resummation for bound-state effects, as well as threshold resummation for emissions of soft and collinear gluons. We discuss uncertainty...
In the high-luminosity era of the Large Hadron Collider, the instantaneous luminosity is expected to reach unprecedented values, resulting in up to 200 proton-proton interactions in a typical bunch crossing. To cope with the resulting increase in occupancy, bandwidth and radiation damage, the ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk). The innermost...
Mass-dependent quark contributions are of great importance to DIS processes. The simplified-ACOT-$\chi$ scheme includes these effects over a wide range of momentum transfers up to next-to-leading order in QCD. In recent years an improvement in the case of neutral current DIS has been achieved by using zero-mass contributions up to next-to-next-to-leading order (NNLO) with massive phase-space...
The top-quark mass is one of the key fundamental parameters of the Standard Model that must be determined experimentally. Its value has an important effect on many precision measurements and tests of the Standard Model. The Tevatron and LHC experiments have developed an extensive program to determine the top quark mass using a variety of methods. In this contribution, the top quark mass...
The precision and reach of physics analyses at the LHC is often tied to the performance of hadronic object reconstruction & calibration, with any incremental gains in understanding & reduced uncertainties being impactful on ATLAS results. Recent refinements to the reconstruction and calibration procedures for jets & missing energy by the ATLAS collaboration has resulted in reduced...
The sPHENIX experiment is a next-generation collider detector at RHIC designed for rare jet and heavy-flavor probes of polarized p+p collisions. The experiment includes a large acceptance, granular electromagnetic calorimeter (EMCal) and very high-rate data acquisition plus trigger system. In RHIC Run-24, sPHENIX sampled 107/pb of transversely polarized p+p collision data at 200 GeV using an...
The Large Hadron electron Collider is a proposed upgrade of the HL-LHC. It will add an energy recovery racetrack to the CERN accelerator complex. The ERL will provide 50 GeV electrons to collide with the LHC beams, resulting in $ep$ ($eA$) collisions with cms energies $\sim 1.2\ (0.75)$ TeV/nucleon and instantaneous luminosities $\sim 10^{34}\ (5\cdot 10^{32}$) cm$^{-2}$s$^{-1}$. It could be...
I present updates related to the parton distribution functions (PDFs) obtained using the MSHT approach. I address inclusion of new data types, e.g. LHC dijet data, studies of strong coupling dependence and determinations, and closure tests and comparison to the neural network approach and implications for best fits and uncertainties.
Measurements of multiboson production at the LHC are important probes of the electroweak gauge structure of the Standard Model and can constrain anomalous gauge boson couplings. In this talk, recent measurements of diboson production by the ATLAS experiment are presented. Inclusive and differential measurements of WW, ZZ and Zy production are highlighted. The results are used to constrain...
Hadronic object reconstruction & classification is one of the most promising settings for cutting-edge machine learning and artificial intelligence algorithms at the LHC. In this contribution, highlights of ML/AI applications by ATLAS to QCD and boosted-object identification, MET reconstruction and other tasks will be presented.
A 10 TeV Muon Collider has been proposed as the next energy frontier machine, with expected physics prospects that far surpasses the current knowledge in a large variety of Standard Model measurements and Beyond Standard Model searches. Due to the short lifetime of muons, however, high-energy electrons that interact with shielding elements produce a large amount of beam-induced background...
The RHICf experiment installed an electromagnetic calorimeter in front of the Zero-Degree Calorimeter (ZDC) of the RHIC-STAR experiment in 2017 to measure the transverse-spin asymmetries of the far-forward neutral particles produced from transversely polarized proton collisions at RHIC. It has been known that the far-forward neutrons have a large transverse-spin asymmetry in RHIC transversely...
We study the impact of state-of-the-art top-quark data collected at the Large Hadron Collider (LHC) on proton parton distribution functions (PDFs) using the ABMP16 methodology. The gluon PDF at large x and the top-quark mass value derived from these data are well compatible with the previous ABMP16 results, but with significantly reduced uncertainties by up to a factor of two. We discuss the...
Supersymmetry (SUSY) provides elegant solutions to several problems in the Standard Model, and searches for SUSY particles are an important component of the LHC physics program. The direct production of electroweak SUSY particles, including sleptons, charginos, and neutralinos, is a particularly interesting area with connections to dark matter and the naturalness of the Higgs mass. Naturalness...
The identification of jets containing b-hadrons is key to many physics analyses at the LHC, including measurements involving Higgs bosons or top quarks, and searches for physics beyond the Standard Model. In this contribution, the most recent enhancements in the capability of ATLAS to separate b-jets from jets stemming from lighter quarks will be presented. The improved performance originates...
Measuring Deeply Virtual Compton Scattering (DVCS) observables offers the most direct access to Generalised Parton Distributions (GPDs), which offer a 3D description of the quark and gluon distributions in position and momentum inside the nucleon. GPDs are essential to understand how the nucleon’s global properties, such as its spin and mass, arise from quarks and gluons.
The extraction of...
We summarize latest developments in the CTEQ-TEA global QCD analysis of parton distributions in the nucleon.
The High-Luminosity Large Hadron Collider (HL-LHC) at CERN marks a new era for high-energy particle physics, demanding significant upgrades to the ATLAS Trigger and Data Acquisition (TDAQ) system. Central to these upgrades is the enhancement of online software tracking capabilities to meet the unprecedented data rates and complexity of HL-LHC operations. This study investigates the deployment...
Global interpretations of particle physics data within the framework of the Standard Model Effective Field Theory (SMEFT), including their matching to UV-complete models, involve energy scales potentially spanning several orders of magnitude.
Relating these measurements in terms of a common energy scale is enabled by the Renormalisation Group Equations (RGEs).
Here we present a systematic...
A number of flagship analyses in the ATLAS experiment rely on real-time b-tagging to efficiently record data. In run 3, the jet and b-jet trigger was updated with state of the art machine learning, to reduce background rates and improve efficiency, while remaining within the constraints of the trigger hardware. We will discuss the design, optimization, deployment, and validation of the ATLAS...
We report on recent advancements in the global determination of the unpolarised proton PDFs by the NNPDF collaboration. Since the previous major release, several improvements have been made in both theoretical frameworks and methodological approaches, supplemented with high-statistic measurements from LHC Run II. On the theoretical front, we present the current state-of-the-art PDF...
This talk presents precise measurement of the properties of the Higgs boson, including its mass, total width, spin, and CP quantum number using the full dataset collected in pp collisions at 13 TeV during Run 2 and at 13.6 TeV during Run 3 of the LHC. The measurements are performed in various Higgs boson production and decay modes, as well as their combinations. Observation of deviations...
We revisit the fragmentation processes $g\to\chi_{cJ}+g$, $g\to\eta_c+g$, $g\to J/\psi+g+g$ and propose and alternative method to regularize the infrared and collinear divergencies. We argue that the conventional technique (i.g., the dimensional regularization) are unphysical, as they expand the perturbation theory beyond its applicability limits. At the same time, the conventional...
We investigate the impact of recently computed N3LO corrections to QCD splitting and DIS coefficient functions on global fits of parton distribution functions (PDFs) using the xFitter framework. By comparing fits performed at different perturbative orders, we analyze the modifications introduced to PDFs and their associated uncertainties, incorporating correlated experimental errors....
The Large Hadron electron Collider is a proposed upgrade of the HL-LHC. It will add an energy recovery racetrack to the CERN accelerator complex. The ERL will provide 50 GeV electrons to collide with the LHC beams, resulting in $ep$ ($eA$) collisions with cms energies $\sim 1.2\ (0.75)$ TeV/nucleon and instantaneous luminosities $\sim 10^{34}\ (5\cdot 10^{32}$) cm$^{-2}$s$^{-1}$. It could be...
The event rates and kinematics of Higgs boson production and decay processes at the LHC are sensitive probes of possible new phenomena beyond the Standard Model (BSM). This talk presents precise measurements of Higgs boson production and decay rates, obtained using the full Run 2 and partial Run 3 pp collision dataset collected by the ATLAS experiment at 13 TeV and 13.6 TeV. These include...
We will discuss several key updates to the MSHT approximate N3LO PDFs; including the combination of these aN3LO QCD PDFs with QED effects, the first determination of the strong coupling constant at aN3LO, and further updates based on new theoretical information available at N3LO including more precise splitting functions for N3LO PDF evolution. All of this work has important consequences for...
In this talk, we present our extension of the concept of maximal quantum entanglement from proton structure to jet fragmentation in proton-proton collisions, establishing a connection between jet fragmentation functions and charged hadron multiplicity [1]. This relationship is tested using ATLAS data from the Large Hadron Collider, showing excellent agreement. As the first study to apply...
The Forward Physics Facility (FPF) is a proposed new facility to house several far-forward experiments at the High Luminosity LHC at CERN. The FPF experiments will deetect more than a million neutrinos in the TeV energy range covering all neutrino flavours, as well as search for a host of new particles. The FPF has a broad physics programme covering BSM searches, neutrino physics, and QCD...
Recent measurements by the PHENIX collaboration of $\eta$ meson spin observables will be presented. The $\eta$ meson is a practical final-state for study: as a light neutral meson, it is abundantly produced in hadronic collisions, while its heavier mass compared to the $\pi^0$ helps mitigate detector effects that limit the reach and precision of its lighter counterpart. At forward rapidity,...
The pursuit of detecting high-energy Higgs boson decays into a pair of heavy quarks is a prominent focus within the ATLAS experiment's physics program. In this study, we introduce an innovative tagger that leverages graph networks and employs tracks as input constituents. Our approach demonstrates a substantial improvement when compared to the previous boosted Higgs boson tagger employed by...
Ultraperipheral collisions of relativistic heavy ion beams lead to a diverse set of photon-nucleus (photonuclear) interactions. Measurements of particles produced in photonuclear reactions can shed light on the QCD dynamics of these novel, extremely asymmetric colliding systems, with energies between those available at RHIC and the LHC. Previous studies by ATLAS have characterized photonuclear...
In this talk, we present the recent searches for new physics in the electroweak sector of the Standard model containing intact protons measured by the CMS Precision Proton Spectrometer (PPS). With the higher event pileup expected in the high-luminosity upgrade of the LHC, a tighter selection of intact protons under increasingly challenging conditions is required. In this view, the PPS2 project...
The strong coupling $\alpha_s(Q^2)$ represents one of the fundamental parameters of the Standard Model, and its precise determination is required a variety of phenomenological applications. We present an updated determination of $\alpha_s(m_Z)$ from the global NNPDF4.0 analysis carried out at approximated N$^3$LO (aN$^3$LO) accuracy, which also accounts for NLO QED corrections and the photon...
We present detailed analysis of the T-even and T-odd lepton angular distribution in the Drell-Yan process including γ/Z^0 gauge boson exchange and using perturbative QCD based on the collinear factorization scheme at leading order in the α_s expansion and α_s^2 for T-odd . We focus on the study of the transverse momentum Q_T dependence of the corresponding hadronic structure functions and...
We present the most recent studies of anomalous couplings of the Higgs boson and its CP structure at the CMS experiment. These studies probe BSM effects, such as CP conserving or CP violating couplings to particles with masses not directly accessible at the LHC through virtual quantum loops. Results in the context of effective field theories (EFT) will also be presented.
In this talk, recent measurements of distributions sensitive to the underlying event, the hadronic activity observed in relationship with the hard scattering in the event, by the ATLAS experiment are presented. Underlying event observables like the average particle multiplicity and the transverse momentum sum are measured for Kaons as Lambda baryons as a function of the leading track-jet and...
We discuss how the two existing approximate N3LO (aN3LO) sets of parton distributions (PDFs) from the MSHT20 and NNPDF4.0 series can be combined for LHC phenomenology, both in the pure QCD case and for the QCD⊗QED sets that include the photon PDF. Using the resulting combinations, we present predictions for the total inclusive cross-section for Higgs production in gluon fusion, vector boson...
A key focus of the physics program at the LHC is the study of head-on proton-proton collisions. However, an important class of physics can be studied for cases where the protons narrowly miss one another and remain intact. In such cases, the electromagnetic fields surrounding the protons can interact producing high-energy photon-photon collisions. Alternatively, interactions mediated by the...
The discovery of the Higgs boson with the mass of about 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 bosons, beyond-the-Standard-Model...
The HERAPDF2.0 parton densities represent the current state of the art in determining the longitudinal structure of the proton using data from Deep Inelastic Scattering (DIS) experiments alone. Their precision is at the few percent level at intermediate Bjorken-x, but deteriorates fast for x-->1 and also below x~10^-3. The high x region in particular can also be constrained using LHC data,...
This work presents the next-to-leading order calculation of the heavy
quark production contributions to the structure functions F4 and F5
within the ACOT formalism in deep inelastic scattering. These struc
ture functions have been largely overlooked in the past, mainly due to
the experimental challenges associated with their measurement. How
ever, forthcoming experimental advancements,...
Many new physics models predict the existence of new, heavy particles. This talk summarises recent ATLAS searches for Beyond-the-Standard-Model heavy resonances which decay to pairs of quarks, or leptons, using Run 2 and or Run 3 data collected at the LHC, as well as searches for Dark Matter with the same datasets.
Fixed target experiments are excellent tools for searching for signals of weak interacting dark matter in the sub-GeV mass region. The concept of dark portals between hidden and ordinary matter, as described by the Standard Model, typically involves light sub-GeV intermediate states. In particular, the dark photon portal will be considered and discussed within the framework of existing and...
Recent studies suggest that global fits of Parton Distribution Functions (PDFs) might inadvertently 'fit away' signs of new physics in the high-energy tails of the distributions measured at the high luminosity programme of the LHC (HL-LHC). This could lead to spurious effects that might conceal key BSM signatures and hinder the success of indirect searches for new physics. In this talk, we...
The Higgs boson discovery at the Large Hadron Collider (LHC) completed the Standard Model (SM). Still, the possibility of additional scalar bosons remains open, provided their contributions to electroweak symmetry breaking are sufficiently small. Recent analyses of LHC data have revealed statistically significant anomalies in multi-lepton final states, characterized by events with multiple...
We explore the potential for extracting the longitudinal proton structure function FL(x, Q2) at the future Electron-Ion Collider (EIC) through a Rosenbluth separation method. The impacts of differing assumptions on systematic uncertainties and beam energy scenarios are investigated. With a sufficiently large number of centre of mass energy configurations, the EIC will measure FL with an...
Motivated by the ion-collision program at the Large Hadron Collider, plans for its high-luminosity upgrade, and on-going discussions for multi-TeV future hadron colliders, we systematically investigate hard-scattering, Standard Model processes in many-TeV ion-ion collisions. We focus on the symmetric beam configurations for Pb-208, Xe-131, C-12, and the proton (for reference), catalog total...
Direct measurements of gravitational form factors (GFFs) are extremely challenging and nearly impossible due to the weakness of gravitational interactions. However, processes such as deeply virtual Compton scattering (DVCS) offer an effective way to study GFFs indirectly by mimicking graviton tensor interactions. Our work integrates insights from experimental physics, lattice QCD, and...
In ultra-relativistic heavy ion collisions, the charged ions produce an intense flux of equivalent photons. Photon-induced processes are the dominant interaction mechanism when the colliding nuclei have an impact parameter larger than the nuclear diameter. In these ultra-peripheral collisions (UPCs), the photon provides a clean, energetic probe of the partonic structure of the nucleus,...
The $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ decay is a golden mode for flavour physics. Its branching ratio is predicted with high precision by the Standard Model to be less than $10^{-10}$, and this decay mode is highly sensitive to indirect effects of new physics up to the highest mass scales. A new measurement of the $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ decay by the NA62 experiment at the...
There have been rapid developments in the direct calculation in lattice QCD (LQCD) of the Bjorken-$x$ dependence of hadron structure through large-momentum effective theory (LaMET) and other similar effective approaches. These methods overcome the previous limitation of LQCD to moments (that is, integrals over Bjorken-$x$) of hadron structure, allowing LQCD to directly provide the kinematic...
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 scintillators are read-out by the wavelength shifting fibres coupled to the photomultiplier tubes (PMTs). The analogue signals from the PMTs are amplified, shaped, digitized by sampling the signal every 25...
The Standard Model of Particle Physics explains many natural phenomena yet remains incomplete. Leptoquarks (LQs) are hypothetical particles predicted to mediate interactions between quarks and leptons, bridging the gap between the two fundamental classes of particles. Vectorlike quarks (VLQs) and Vectorlike leptons (VLLs) lie at the heart of many extensions seeking to address the Hierarchy...
The start of the operation of the High Luminosity LHC (HL-LHC) is planned for the year 2030. The associated increase in luminosity provides an opportunity for further scientific discoveries as while also introducing many technical challenges for the systems of the ATLAS experiment. The HL-LHC environment has necessitated the Phase-II upgrade of the ATLAS hadronic Tile-Calorimeter (TileCal)...
We investigate the systematic uncertainties and potential biases arising from the inclusion of large-$x$ corrections to proton and deuteron DIS data in global QCD analyses. Using the CTEQ-JLab framework, we examine various approaches to implementing higher-twist corrections in nucleon structure functions and off-shell PDF modifications in deuteron targets. We analyze how these components...
The production of quarkonia, and in particular $J/\psi$, at the EIC is a valuable tool to probe the gluon transverse momentum dependent (TMD) distributions at lower energies as compared, for instance, to Higgs production. However, the proper factorization must be adopted to describe $J/\psi$ production at small transverse momentum accurately. This requires the introduction of a new TMD object,...
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...
In ultra-relativistic heavy-ion collisions, large rates of $\gamma\gamma$ processes occur through the interaction of the large electromagnetic fields of the nuclei. These $\gamma\gamma$ interactions enable the study of processes potentially sensitive to physics beyond the Standard Model. In ultra-peripheral collisions (UPCs), characterized by large impact parameter between the nuclei, the...
Fantômas is a C++ module implemented in xFitter for universal approximation of parton densities and other quantum correlator functions using Bézier curves. We review its operating principles and an application of the Fantômas framework to obtain parton distributions in a charged pion with detailed estimates of parametrization and nuclear uncertainties.
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,...
Primary focus of the Spin Physics Detector (SPD) at the Nu-
clotron based Ion Collider fAcility (NICA) is to study nucleon spin
structure in the three dimensions. At the SPD, measurements of
cross-sections and spin asymmetries sensitive to the unpolarized and
various polarized (helicity, Sivers, Boer-Mulders) gluon distributions
will be performed. Measurements from collisions of polarized...
The Belle and Belle II experiments have collected a 1.1 ab$^{-1}$ sample of $e^+ e^-\to B\bar{B}$ collisions at a centre-of-mass energy corresponding to the $\Upsilon(4S)$ resonance. These data, with low particle multiplicity and constrained initial state kinematics, are an ideal environment to search for rare electroweak penguin $B$ decays and lepton-flavour violating decays to final states...
A comprehensive quality assurance testing procedure is developed to ensure the reliability of transformer-coupled buck converter boards (Bricks) within the ATLAS hadronic Tile Calorimeter (TileCal). With the impending Phase-II upgrades of the TileCal, which will contribute to the success of the forthcoming High-Luminosity Large Hadron Collider, ensuring the reliability of the Bricks in the...
The Phase II upgrade of the ATLAS experiment at CERN represents a significant advancement in preparing for the High Luminosity Large Hadron Collider (HL-LHC) era. This upgrade includes substantial enhancements to the detector, particularly the integration of radiation-resistant transformer-coupled buck converters, referred to as Low Voltage Power Supply (LVPS) bricks. A thorough quality...
In this talk we will critically assess the robustness of uncertainties on parton distribution functions (PDFs) determined using neural networks from global sets of experimental data collected from multiple experiments. The determination of PDFs is an inverse problem, and we study the way the neural network model tackles it when inconsistencies between input datasets are present. We use a...
In this presentation, I will discuss recent advancements in NNLO+PS predictions for top-quark pair production and decay within the MiNNLO framework. MiNNLO provides a robust method for incorporating next-to-next-to-leading order (NNLO) QCD corrections directly into fully differential predictions, offering unprecedented accuracy. This approach enables a consistent treatment of both production...
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 Neutral Particle Spectrometer (NPS) in Hall C of the Thomas Jefferson National Accelerator Facility (aka Jefferson Lab) is a standalone electromagnetic calorimeter for detecting high energy photons. The NPS science program is a suite of ten approved precision experiments of small cross sections divided into two run groups. The first run group, RG1A, consists of the measurement of exclusive...
New physics can manifest itself via lepton-flavour-violating processes in LHC proton-proton collisions. In the past years, different experiments have reported possible indications of new physics violating the lepton-flavour-universality symmetry of the Standard Model. This talk summarizes the most recent searches and precision measurements for lepton-flavour-violating processes with the CMS...
The Large Hadron Collider (LHC) will undergo its high-luminosity upgrade to increase its luminosity, affecting the ATLAS detector and, consequently, its hadronic Tile-Calorimeter (TileCal). As a part of the ATLAS Phase-II Upgrade project to adapt to the new high-luminosity environment, the TileCal is upgrading its low-voltage power supplies that power its on-detector front-end electronics....
Studying heavy-flavour hadron properties provides a extensive tests for various QCD predictions as well as a means to probe the Standard Model validity. ATLAS experiment, being a general-purpose detector at LHC, is particularly successful in such measurements with final states involving muons, thanks to large collected integrated luminosity and precise muon reconstruction and triggering. This...
I will analyse the theoretical uncertainties inherent in the determination of the strong coupling from the transverse momentum (pT) spectrum of the Z boson. Such analyses require fine control of percent-level theoretical effects in small pT region, not only in terms of their magnitude but also of their shape and that of the corresponding theoretical uncertainties. This is theoretically...
We present the first proof of concept extraction using neural networks (NNs) of the unpolarised transverse-momentum distributions (TMDs) at next-to-next-to-next-to-leading logarithmic(N$^3$LL) accuracy. By offering a more flexible and adaptable approach, NNs overcome some of the limitations of traditional functional forms, providing a better description of data. This work focuses exclusively...
Long-lived particles (LLPs) produced at the LHC travel a macroscopic distance before decaying, producing a unique experimental signature. This is an ideal probe for searching beyond standard model physics and the CMS collaboration has a wide program covering different final states. Recent results on CMS searches for LLP decaying to leptons and hadrons is presented focusing both on inclusive...
Accurately propagating uncertainties is essential for parton distribution functions (PDFs), particularly with the high-precision data expected from the HL-LHC. Traditional methodologies often struggle with strong non-linear dependencies in parameters, underscoring the need for innovative approaches. In this talk, we introduce Colibri, a flexible Bayesian analysis framework for PDFs, enabling...
The Belle and Belle II experiments have collected a $1.4~\mathrm{ab}^{-1}$ sample of $e^+e^-$ collision data at centre-of-mass energies near the $\Upsilon(nS)$ resonances. These data include a 19.2 fb$^{-1}$ sample of data collected at centre-of-mass energies near the $\Upsilon(10753)$ resonance. We present several results related to the following processes: $e^+e-\to \Upsilon(nS)\eta$,...
ATLAS is currently preparing for the HL-LHC upgrade, with an all-silicon Inner Tracker (ITk) that will replace the current Inner Detector. The ITk will feature a pixel detector surrounded by a strip detector, with the strip system consisting of 4 barrel layers and 6 endcap disks. After completion of final design reviews in key areas, such as Sensors, Modules, Front-End electronics and ASICs, a...
One of the big challenges facing proton spin structure is the unexpectedly large transverse single spin asymmetries (TSSA, AN ) in transversely polarized $p^\uparrow + p$ collisions. Significant non-zero TSSAs in inclusive hadron productions at forward rapidities have been observed in many experiments, including those at RHIC. Despite extensive theoretical efforts, including twist-3...
The measurement of dijets in proton-lead collisions at the LHC offers unique possibilities for investigating both nuclear and nucleon initial state effects as a function of parton scattering kinematics. In particular, color fluctuation effects can significantly alter the average interaction strength of the proton, affecting the number of nucleon-nucleon interactions with the Pb nucleus and,...
Recent highlights of searches for additional non-standard-model Higgs bisons from the CMS experiment are presented.
The H1 Collaboration reports the first measurement of the 1-jettiness event shape observable $\tau_1^b$ in neutral-current deep-inelastic electron-proton scattering (DIS). The observable $\tau_1^b$ is equivalent to a thrust observable defined in the Breit frame. The data sample was collected at the HERA $ep$ collider in the years 2003--2007 with center-of-mass energy of $\sqrt{s}=319$ GeV,...
We present a new global analysis of nuclear PDFs in the nCTEQ approach. Building on a modern proton baseline without nuclear data and extending the kinematic range, we combine and update previous separate analyses that focused on JLab neutral-current DIS, neutrino DIS and dimuon production, and the currently available LHC data, in particular on W/Z-boson and heavy-quark production. For the...
The ATLAS experiment in the LHC Run 3 uses a two-level trigger system to select events of interest to reduce the 40 MHz bunch crossing rate to a recorded rate of up to 3 kHz of fully-built physics events. The trigger system is composed of a hardware based Level-1 trigger and a software based High Level Trigger. The selection of events by the High Level Trigger is based on a wide variety of...
Within the nCTEQ collaboration, we have developed a novel nuclear parton distribution function (nPDF) framework inspired by Short-Range Correlations (SRCs) to bridge the nuclear and particle physics descriptions of nuclei. Initial investigations show that this SRC-based approach yields improved fits as compared to traditional methods, suggesting it may better capture nuclear properties....
The H1 Collaboration at HERA reports the first measurement of groomed event shape observables in deep inelastic electron-proton scattering (DIS) at $\sqrt{s}=319$ GeV, using data recorded between the years 2003 and 2007 with an integrated luminosity of 351 pb$^{-1}$. Event shapes provide incisive probes of perturbative and non-perturbative QCD. Grooming techniques have been used for jet...
The ATLAS experiment at CERN is constructing upgraded system for the "High Luminosity LHC", with collisions due to start in 2030. In order to deliver an order of magnitude more data than previous LHC runs, 14 TeV protons will collide with an instantaneous luminosity of up to 7.5 x 10e34 cm^-2s^-1, resulting in much higher pileup and data rates than the current experiment was designed to...
With the conclusion of proton-proton collision data-taking in 2024, the ATLAS experiment has now integrated a luminosity exceeding 180 fb^{-1} during the Run 3 period, which began in July 2022 following Long Shutdown 2 (LS2). During LS2, a series of detector upgrades were implemented, including the installation of the New Small Wheel (NSW), a major upgrade that involved replacing the innermost...
I report on recent progress in SHERPA's simulation of QCD processes in DIS and photo-production at current and future collider experiments.
The study of the production of single W and Z bosons at the LHC, inclusive and in association with jets, provides stringent tests of the electroweak theory and perturbative QCD. The ATLAS experiment has measured the W boson production cross section and the W-boson charge asymmetry as a function of lepton rapidity in special LHC runs with reduced instantaneous luminosity at 5 and 13 TeV....
Perturbative solutions for unpolarized QED parton distribution and fragmentation functions are presented explicitly in the next-to-leading logarithmic approximation. The scheme of iterative solution of QED evolution equations is described in detail. Applications of the QED PDFs and fragmentation functions for calculation of higher-order radiative corrections to processes of electron-positron...
The Large Hadron electron Collider is a proposed upgrade of the HL-LHC. It will add an energy recovery racetrack to the CERN accelerator complex. The ERL will provide 50 GeV electrons to collide with the LHC beams, resulting in $ep$ ($eA$) collisions with cms energies $\sim 1.2\ (0.75)$ TeV/nucleon and instantaneous luminosities $\sim 10^{34}\ (5\cdot 10^{32}$) cm$^{-2}$s$^{-1}$. It could be...
Due to the inclination for forward gauge radiation, lepton colliders beyond a few TeV are effectively electroweak boson colliders, suggesting the treatment of electroweak bosons as constituents of high-energy leptons. In this talk, we summarize the status of electroweak boson parton distribution functions, present new theoretical progress on their implementation, and give a brief outlook for...
The Electron-Ion Collider (EIC) will provide a unique experimental platform to explore the properties of gluons in nucleons and nuclei, offering new insights into their structure and dynamics. The EIC community has outlined a detailed physics program in the White Paper and identified the demanding detector requirements in the Yellow Report. The primary general-purpose detector, ePIC, is...
The ever-growing ecosystem of beyond standard model (BSM) calculations and parametrizations has motivated the development of systematic methods for making quantitative cross-comparisons over the wide range of possible models, especially with controllable uncertainties. In this talk, we highlight how the language of uncertainty quantification (UQ) furnishes useful metrics for assessing...
The future Electron Ion Collider (EIC) will offer a unique opportunity to explore the parton distributions inside nucleons and nuclei thanks to an unprecedented luminosity, a wide range of energies, a large choice of nuclei and polarization of both beams.
The electron Proton-Ion Collider (ePIC) detector will be capable of precise determination of the position of primary and secondary...
The FASER experiment at the LHC is designed to search for light, weakly-coupled new particles, and to study high-energy neutrinos. The experiment has been running since 2022, and has collected nearly 200/fb of pp collision data. FASER has released several neutrino results including the first observation of electron and muon neutrinos at a particle collider, the first measurement of the muon...
High energy two-photon processes provide unique opportunity for studying with high precision the electroweak sector of particle interactions at future colliders. In particular, future facilities such as the LHeC, FCC-eh, or the eh-CEPC, will ensure very advantageous experimental conditions and at the same time provide high two-photon luminosities, reaching the TeV scale. In this talk we will...
Using modern machine learning, a measurement of all outgoing particles from high $Q^2$ electron-proton collisions is presented using data recorded with the H1 detector at HERA. The resulting differential cross section is unbinned and multi-dimensional, yet unfolded to the particle level. It thus allows for flexible reinterpretations.
We estimate the accuracy with which the coefficient of the lepton flavour-violating dimension-six operators can be measured at the proposed electron-proton collider.
Cuts-based analysis is performed to compute the signal significance at the centre of mass energy of 1.3 TeV, with a total of 3 ab$^{-1}$ integrated luminosity. Using the optimal observables method for the kinematic...
Jet cross-section ratios between inclusive bins of jet multiplicity are measured differentially in variables that are sensitive to either the energy-scale or angular distribution of hadronic energy flow in the final state. Several improvements to the calibration of jets are described, which result in significant improvements in the overall jet energy scale uncertainty. The measurements are...
We address long-standing problems in the muon anomalous magnetic moment, the observed relic density, and the recent measurements by the CMS and ATLAS collaborations of the Higgs decay signal strength in h→Zγ using a common framework. This framework incorporates the coupling of axion-like particles (ALPs) with charged leptons and electroweak gauge bosons. In this talk, we will present bounds on...
We determine the value of the strong coupling α_s and study its running over a wide range of scales as probed by the dijet production process at hadron colliders. The analysis is performed using the complete next-to-next-to-leading order (NNLO) predictions in perturbative QCD and is based on dijet data published by ATLAS and CMS at center-of-mass energies of 7, 8, and 13 TeV. From a large...
We investigate the anomalous $t \bar{t} Z$ couplings in the Standard Model (SM) and measure the precision of couplings beyond the SM in future electron-proton collider environments. In the analysis, $t \bar{t}$ quark pairs are produced in the neutral currents channel through the collision process $e^{-} p \to e^{-} t \bar{t}$, for electron and proton (unpolarized) beam-energies $E_{e}=60$ GeV...
Jets, the collimated streams of hadrons resulting from the fragmentation of highly energetic quarks and gluons, are some of the most commonly observed radiation patterns in hadron collider experiments. The distribution of quantum chromodynamic (QCD) radiation within jets is determined by complex processes, the production of showers of quarks and gluons and their subsequent recombination into...
The observed indications of a new scalar resonance around 95 GeV, initially reported by LEP and supported by CMS and ATLAS in di-photon, $\tau\tau$, and $W^+W^-$ channels, motivate exploring its discovery potential at future electron-positron colliders. This study focuses on the production of the new scalar (S) in $e^+e^- \to ZS$ process with $Z \to \mu^+\mu^-$ and $S \to b\bar{b}$ and...
In this work we calculate the differential cross section for the $J/\psi$ production in electron proton scattering. We use the $k_T$ factorization approach with unintegrated gluon distribution function. We present distributions in transverse momentum and rapidity for COMPASS, JLab, HERMES and Electron Ion Collider centre of mass energies. Our results are compared with the experimental data for...
QCD factorization takes on different forms in the large-x and the small-x regimes. In the large-x motivated collinear factorization, one gets the DGLAP evolution equation, whereas, in the small-x motivated rapidity factorization, the BFKL equation is the major player. To unify different regimes, a new TMD factorization based on the background field method is proposed, which not only reduces to...
The Phase II upgrade at CERN represents a significant advancement in preparing for the High Luminosity Large Hadron Collider (HL-LHC) era. This upgrade includes substantial enhancements to the detector systems, particularly the integration of radiation-resistant transformer-coupled buck converters, referred to as LVPS bricks. A thorough quality assurance process is being implemented to improve...
We study the exclusive production of $J/\psi$ in the photon-proton scattering using a hot spot model. The hot spot model is formulated in the framework of the MV model and in the dilute limit, which enable us to derive the analytical expressions for both coherent and incoherent cross sections. We determine analytically the contributions to the coherent and incoherent cross section from...
We present an implementation of the Balitsky-Kovchegov (BK) evolution equation solver using differentiable programming. First and second derivatives of the amplitude with respect to the initial condition parameters are automatically calculated at all stages of the simulation. This should considerably facilitate and speed up the procedure of fitting initial condition parameters to data....
I report on recent process in the simulation of diffractive processes in SHERPA.
One of the main approximations adopted in the Color Glass Condensate (CGC) is the so-called eikonal approximation, which amounts to neglecting power-suppressed corrections in the high-energy limit. This approximation is well justified for asymptotically high energies. However, the corrections to it might be sizable in the upcoming Electron Ion Collider. The next-to-eikonal order cross-section...
As experimental data is becoming more precise, understanding the impact of the uncertainties in the errors,
especially the systematic errors, is increasingly becoming a significant focus of PDF groups. In this talk I will
explain how the error on errors can be modelled and how this framework can be applied to both uncorrelated
and correlated systematic errors. We will then investigate...
We will report the status of the milliQan experiment at CERN. The milliQan "bar" detector was completed in June 2023 and has been taking physics data since then. The milliQan "slab" detector was completed in Fall of 2024 and is being commissioned. We will give an update on the readiness of the slab detectorfor physics data taking. Finally, we will present first physics results on the search...
The study of hadronization—the process by which quarks and gluons transition into hadrons—is fundamental to understanding the strong interaction dynamics within quantum chromodynamics (QCD). Using the CLAS12 detector at Jefferson Lab, the Run Group E (RGE) experiment offers unprecedented insights into hadronization in the nuclear medium. This talk will present preliminary results from the...
We present calculations of higher-order QCD and electroweak (EW) corrections to the associated production of a top-antitop quark pair and a Z boson, i.e. $t{\bar t}Z$ production, in proton collisions. We find that the contributions from soft-gluon corrections are numerically dominant and large. We present approximate NNLO (aNNLO) and approximate N$^3$LO (aN$^3$LO) cross sections that include...
I present a scheme of NLO computations for generic observables in high-energy collisions within the framework of hybrid high-energy factorization, that is with one off-shell initial-state parton. The scheme is obtained by taking a high-energy limit of the NLO computation in collinear factorization. Terms belonging to the projectile and the target are identified, and the ambiguity of this...
Ultra-peripheral collisions (UPCs) in high-energy heavy-ion collisions provide a unique environment to study a wide range of electromagnetic processes, mediated by virtual photons. In Run 3 of the LHC, the ALICE experiment has begun exploring inclusive photonuclear interactions, where a photon interacts with a nucleus, resulting in its breakup, gamma+A --> X. These interactions include both...
With a large momentum transfer, high energy lepton-hadron deep inelastic scattering induces both QCD and QED radiations. In this talk, we present the first NLO calculation of inclusive single hadron/jet production at large transverse momentum in lepton-hadron scattering in a joint QCD and QED factorization approach [1]. Both QCD and QED collision-induced radiation are treated equally and...
We promote our leading order analysis [1] determining the initial condition of the Balitsky-Kovchegov (BK) evolution equation to the next-to-leading order treatment, using both the NLO BK equation and NLO impact factors. The initial condition, to be described by the posterior distribution obtained via Bayesian optimization, is constrained by the total cross section and charm quark production...
With the LHC transitioning to a precision measurement machine, the proton Parton Distribution Functions (PDFs) are becoming a leading source of uncertainty in analyses such as the measurements of top quark mass or the Higgs boson width. Furthermore, the high-momentum-fraction (high-x) regime is of particular interest when probing the most energetic collisions at the LHC. Thus, it is crucial to...
In ultra-relativistic heavy ion collisions, the charged ions produce an intense flux of equivalent photons. Photon-induced processes are the dominant interaction mechanism when the colliding nuclei have an impact parameter larger than the nuclear diameter. In these ultra-peripheral collisions (UPCs), the photon provides a clean, energetic probe of the partonic structure of the nucleus,...
A key open question in the study of multi-particle production in high-energy $pp$ collisions is the relationship between the ``ridge'' - observed azimuthal correlations between particles in the underlying event that extend over all rapidities and hard or semi-hard scattering processes. In particular, it is not known whether jets or their soft fragments are correlated with particles in the...
The Breit frame provides a natural frame to analyze lepton--proton scattering events. In this reference frame, the parton model hard interactions between a quark and an exchanged boson defines the coordinate system such that the struck quark is back-scattered along the virtual photon momentum direction. In Quantum Chromodynamics (QCD), higher order perturbative or non-perturbative effects can...
The measurement of dijets in proton-lead collisions at the LHC offers unique possibilities for investigating both nuclear and nucleon initial state effects as a function of parton scattering kinematics. In particular, color fluctuation effects can significantly alter the average interaction strength of the proton, affecting the number of nucleon-nucleon interactions with the Pb nucleus and,...
It is well known that the back-to-back correlation limit of inclusive quark-antiquark dijet production in unpolarized high energy electron-proton collisions can probe the Weizsacker-Williams (WW) gluon distribution at small x. In this talk, we consider double-spin asymmetry for inclusive quark-antiquark dijet production in longitudinally polarized electron proton/nucleus scatterings at high...
Muon Collider is a unique machine that allows to achieve with a single facility both high energy reach and clean collision signature in a small environmental footprint. In particular, a collider with the centre-of-mass energy of 10 TeV is the long-term target of the ongoing international design study, while lower intermediate energies are also considered. Despite its much smaller size and...
A recently completed calculation of next-to-next-to-leading QCD corrections to the weak radiative B-meson decay is going to be reported. Contrary to previous estimates of these corrections, no interpolation in the charm quark mass is necessary. Next, the current status of determining perturbative and non-perturbative contributions to the inclusive semileptonic B-meson decays is going to be discussed.
In ultra-relativistic heavy-ion collisions, large rates of $\gamma\gamma$ processes occur through the interaction of the large electromagnetic fields of the nuclei. These $\gamma\gamma$ interactions enable the study of processes potentially sensitive to physics beyond the Standard Model. In ultra-peripheral collisions (UPCs), characterized by large impact parameter between the nuclei, the...
Employing the heavy quark expansion model with the kinetic scheme, we evaluate $\alpha_S(m_c^2)$, the strong coupling constant at the charm quark mass $m_c$ with data on inclusive semileptonic decays of charmed mesons. Using the experimental values of semileptonic decay widths of the $D^0$ and the $D^+$, the value of $\alpha_{s}(m_c^{2})$ is determined to be $0.445\pm0.009\pm0.114$, where the...
We study the internal structure of the deuteron at the level of its partons using the basis light-front quantization approach. The Hamiltonian is constructed by incorporating the fundamental QCD interactions arising from the six-quarks and six-quarks-gluon Fock components. We examine the deuteron’s electromagnetic form factors, parton distribution functions, and tensor-polarized properties....
Basis light-front quantization (BLFQ) is a fully relativistic, nonperturbative approach that employs a light-front quantized Hamiltonian with Quantum Chromodynamics (QCD) inputs, aiming for first-principles calculations. For QCD applications in limited Fock space of the nucleon, we incorporate effective confinement into the Hamiltonian, achieving results consistent with global fits and...
