Assemblée Générale 2026 du GDR QCD

Liste des Contributions

36. Welcome to Subatech

Pol-Bernard Gossiaux

07/10/2026 14:00

37. 2026 GdR QCD AG

Audrey Francisco (CEA), M. Gines MARTINEZ (Subatech CNRS/IN2P3 - IMT Atlantique - Nantes Universite), Raphaël DUPRE, Savvas Zafeiropoulos (CPT Marseille, CNRS)

07/10/2026 14:05

28. The proton charge radius puzzle: observation, bias and scientific rigor.

Adam HOBALLAH (IJCLab CNRS-IN2P3)

07/10/2026 14:20

The repeated measurements of the proton charge radius have led to more precise estimations of this essential quantity in physics. However, driven by the same attempt to improve the precision of the measurements of the radius, researchers unintentionally tend to validate previous findings leading in some cases to inconsistencies. The proton radius puzzle constitutes a clear example of how...

30. Reconstructing generalized parton distributions with neural fields: what the data leave free

Marija Cuic (Irfu, CEA, Université Paris-Saclay/Aidas)

07/10/2026 14:50

Generalized parton distributions (GPDs) encode the three-dimensional partonic structure of the nucleon, but exclusive processes such as deeply virtual Compton scattering constrain them only in part of their kinematic domain — the so-called DGLAP region — while leaving the complementary ERBL region essentially undetermined by data. A standard way to relate the two is through the double...

32. Deeply Virtual Compton Scattering off 4He with the ALERT experiment and CLAS12 spectrometer at Jefferson Lab

Félix TOUCHTE CODJO (PHE/JLab-EIC)

07/10/2026 15:10

1

The goal of the ALERT experiment is to advance the understanding of the QCD structure of the nuclear matter. It proposes a precise measurement of the electro production of a real photon through the interaction with $^4\mbox{He}$ and $^2\mbox{D}$ targets. This process, referred to as Deeply Virtual Compton Scattering (DVCS), gives access to Generalized Parton Distributions (GPDs). The GPDs are...

3. Gluon production in the Color Glass Condensate from BCFW recursion

Francois Gelis (IPhT)

07/10/2026 15:30

In the Color Glass Condensate framework, the colliding projectiles are
described as classical color currents. Gluon production at leading
order in the coupling is obtained from the retarded solution of the
classical Yang-Mills equations, with these currents acting as sources.
However, while the final gluon spectrum is gauge invariant, the
classical color field from which it is obtained is...

11. Probing nPDF at the LHC using electromagnetic processes and quarkonia

Djessy BOURGEAIS (Subatech UMR6457)

07/10/2026 15:50

1

Extracting parton distribution function is crucial for understanding the physic of colliders, since it represent the probability distribution of partons inside a hadron. Recent PDF collaborations as NNPDF, EPPS or CTEQ have used recent LHC data on quarkonia and/or charmed mesons to improve the uncertainty of nPDF at small values of $x$. However, those particles are actually sensitive to...

6. Overview of precision QCD calculations

Hua-Sheng Shao (CERN)

07/10/2026 16:40

In this talk, I will provide an overview of some recent results in precision QCD calculations, with particular emphasis on fixed-order results.

45. Bridging information from lattice and phenomenology on the Collins-Soper kernel

Matteo Cerutti (CEA Paris-Saclay)

07/10/2026 17:10

In this talk, I will present the first joint extraction of the Collins–Soper kernel (CSK) combining experimental and lattice QCD data within a transverse-momentum-dependent (TMD) analysis. The CSK governs the evolution of TMD distributions and is a key ingredient in their phenomenological extraction. We investigate the impact of lattice information through both Bayesian reweighting of an...

4. Quarkonium and HF, Quo Vadis

Pol-Bernard Gossiaux

07/10/2026 17:30

Une petite revue sympathique, sans prétention et très biaisée de certains développements théoriques récents..

19. Vector meson photoproduction as a probe of nuclear structure at the LHC

Olga Bessidskaia Bylund

07/10/2026 17:50

In ultra-pheripheral photo-nuclear interactions, the colliding ions are separated by more than the sum of their radii and the reaction proceeds via photon emission from one nucleus followed by interaction with the target nucleus. A vector meson can be produced if the photon interacts with gluons in the target. Such processes are sensitive to the nuclear structure, including modifications to...

10. Upsilon hadroproduction and vector meson photoproduction with SMOG2 at LHCb

Federica FABIANO (IJCLab (CNRS/IN2P3, Univ. Paris-Saclay))

07/10/2026 18:10

Abstract:

The SMOG2 fixed-target system at LHCb provides a unique opportunity to study cold nuclear matter effects and nuclear structure in a complementary kinematic region with respect to collider measurements. This contribution presents the first measurement of the production of the $\Upsilon(nS, n=1,2,3)$ states in fixed-target collisions where the three states are separately...

40. Probing the Standard Model to eleven digits with the muon magnetic moment

Laurent Lellouch (CNRS & Aix-Marseille U.)

08/10/2026 09:10

The Muon g−2 Experiment at Fermi National Accelerator Laboratory recently published the results of its six-year data-taking campaign, reporting a measurement of the muon's anomalous magnetic moment with unprecedented precision of 0.127 parts per billion, providing one of the most stringent tests of the Standard Model. However, to fully leverage this experimental tour de force in the search for...

33. Muon g-2: an overview of hadronic contributions

Anton Rebhan (Vienna University of Technology (TU Wien))

08/10/2026 09:30

The latest Standard Model prediction of the muon anomalous magnetic moment is now consistent with the experimental value, but it has an uncertainty that is more than four times larger than the experimental error. To fully exploit the experimental result as a constraint on or indicator for BSM physics, the Standard Model prediction needs to be further improved. The theoretical uncertainty is...

20. Next-to-leading Order QCD Factorization for Energy Flow in Electron-Ion Collisions at Twist 4

Omar Elgedawy (Ecole Polytechnique, CPHT)

08/10/2026 09:50

Energy-energy correlators (EECs) have recently emerged as powerful, rigorously established infrared- and collinear-safe (IRC-safe) observables for probing QCD dynamics in the vacuum. However, their IRC safety and factorization properties in the presence of a nuclear medium remain unexplored. In this talk, I will present the first derivation of QCD factorization at next-to-leading order (NLO)...

14. Measurement of the $b$-jet production cross section in proton-proton collisions at $\sqrt{s} = 13.6$ TeV

CLEMENT LOTTEAU

08/10/2026 10:10

Measuring $b$-jet production in proton--proton (pp) collisions is important to test perturbative Quantum Chromodynamics (pQCD) calculations and form a baseline for heavy-ion collision systems. In this contribution, the measurement of $b$-jet production cross section in pp collisions at $\sqrt{s}=13.6$ TeV with ALICE is presented. Charged jets are reconstructed at mid-rapidity...

22. Spatially inhomogeneous confinement-deconfinement phase in rotating quark-gluon plasma

Maxim Chernodub (Institut Denis Poisson, Tours)

08/10/2026 11:00

Using first-principles numerical simulations, we find a new spatially inhomogeneous phase in a rotating (quark-)gluon plasma in thermal equilibrium. This mixed phase simultaneously contains regions of both confining and deconfining states in thermal equilibrium, separated by a spatial transition. We calculate the critical temperature of the local transition as a function of angular velocity...

16. SUBA-Jet 1.2: Incorporating Coherence Effects in Jet Evolution through a Quark–Gluon Plasma

Fabrizio Murgana (Subatech, Nantes)

08/10/2026 11:20

We present SUBA-Jet 1.2, a new version of the SUBA-Jet Monte Carlo framework that incorporates medium-induced coherence effects in the evolution and energy loss of jets propagating through a quark-gluon plasma (QGP). The model combines a vacuum-like parton shower with medium-induced interactions described through a BDMPS-inspired approach.

Coherence is implemented through angular ordering...

13. Heavy-flavour jet measurements with ALICE

Yoshini BAILUNG (Institut de Physique des 2 Infinis (IP2I) de Lyon, CNRS-IN2P3, Université de Lyon)

08/10/2026 11:40

Measurements of heavy-flavour jets in pp collisions provide important tests of Quantum Chromodynamics (QCD) calculations. Jet substructure observables offer insight into the parton-shower evolution and the different radiation patterns of quarks and gluons arising from the different Casimir colour factors and parton masses. Comparisons between jets containing heavy-flavour baryons or...

8. Heavy-ion data match finite-temperature lattice QCD

Jean-Yves OLLITRAULT (IPhT Saclay)

08/10/2026 12:00

A precise value of the speed of sound of QCD at a temperature T=220 MeV can be extracted from 2024 ATLAS data in ultracentral Pb+Pb collisions. One observes an increase of the mean transverse momentum with the charged multiplicity for the 0.4% most central collisions. This increase stems from an increase in the temperature, from which one can extract the speed of sound after careful...

25. Data driven approach to jet tomography

Yacine Mehtar-Tani (BNL)

08/10/2026 12:20

Jet tomography aims to reconstruct the properties of the quark-gluon plasma from the modification of energetic particles and jets traversing it. Because jets contain many intertwined length and time scales, no single observable provides a complete image of their interaction with the medium. I will discuss a multi-messenger approach to jet tomography in which inclusive jet suppression,...

29. Toponium at the LHC: a new frontier in top-quark physics

Prof. Benjamin Fuks (LPTHE Paris / Sorbonne Université)

08/10/2026 14:05

The top quark, the heaviest known elementary particle, has long been thought unable to form bound states. However, intriguing hints in recent LHC data suggest that toponium, a short-lived quasi-bound state of a top-antitop pair, might have left observable traces in data and perhaps even been observed for the first time. In this talk, I will discuss why toponium provides a unique laboratory for...

31. Measurements of top-quark pair production at the threshold at the LHC

Emilien Chapon (CEA / Irfu / DPhP)

08/10/2026 14:30

Recent data from the Large Hadron Collider has enabled groundbreaking measurements of top quark properties, particularly those sensitive to the tt̄ (top-antitop) threshold region. This includes exploring phenomena like the contributions of quasi-bound states ("toponium"), which were once inaccessible. This talk will review the latest advancements in this field from the ATLAS and CMS collaborations.

27. AI/ML Assisted Tracking for the Central Detector of the CLAS12 Experiment

Mathieu Ronayette (CEA Saclay)

08/10/2026 14:50

The CLAS12 experiment is a fixed-target experiment located at the Thomas Jefferson Laboratory in Newport News, USA and dedicated to the study of hadronic physics, in particular the structure of the nucleon and hadron spectroscopy.

The Central Detector (CD) of CLAS12 provides tracking capabilities for charged-particle at large polar angles. However background hits from electronic noise or...

48. Deep-Learning for charged particle tracking

Corentin Allaire (IJCLab, Université Paris-Saclay, CNRS/IN2P3)

08/10/2026 15:10

he reconstruction of particle trajectories is a key challenge of many high-energy and nuclear physics experiments. Indeed, its performance directly impacts particle identification and physics performances while also representing one of the primary CPU consumers of many experiments. As the luminosity of particle colliders increases, this reconstruction will become more challenging and...

38. High-energy nuclear collisions: a new laboratory for many-body nuclear dynamics

Giuliano Giacalone

08/10/2026 15:30

Relativistic nuclear collisions have emerged as a new laboratory for studying many-body correlations among nucleons in nuclear ground states. Focusing on ultra-central collisions, where nearly all nucleons participate, I will discuss how long-range nuclear correlations leave distinct imprints in final-state multi-particle correlation observables, and how scale separations inherent to the QCD...

47. Hadron 2030

BARBARA ERAZMUS (IN2P3/CNRS)

08/10/2026 16:00

42. Table Ronde : Prospectives GdR QCD

Audrey Francisco (CEA), M. Gines MARTINEZ (Subatech CNRS/IN2P3 - IMT Atlantique - Nantes Universite), Herve Moutarde (CEA-IRFU-SPHN), Marcella Grasso (IN2P3), Matteo Cacciari (LPTHE), Raphaël DUPRE, Savvas Zafeiropoulos (CPT Marseille, CNRS), Stefano Matthias Panebianco (French Ministry of Research and Innovation)

08/10/2026 16:45

46. QCD physics at FCC-ee

Matteo Marcoli (CERN)

09/10/2026 09:10

The electron-positron stage of the Future Circular Collider (FCC-ee) is aiming at direct and indirect searches for physics beyond the SM in a new 91-km tunnel at CERN. In addition, the FCC-ee offers unique possibilities for high-precision studies of the strong interaction in the clean environment provided by ee collisions, thanks to its broad span of center-of-mass energies, ranging from the Z...

49. Charmonium production in Pb–-Pb collisions at forward rapidity with ALICE

Sara GARETTI (IJCLab, Université Paris-Saclay)

09/10/2026 09:40

Quarkonium production in high-energy heavy-ion collisions is a key tool to study the production and the properties of the quark-gluon plasma (QGP), a state of matter in which quarks and gluons are no longer confined inside hadrons.

Charmonia are quarkonium bound states consisting of a charm and an anti-charm quark.
Charmonium production in Pb--Pb collisions is sensitive to the quark–gluon...

21. Renormalon subtracted nonrelativistic QCD for heavy hadron systems

M. Simon VAIVA (CPT Marseille)

09/10/2026 10:00

Precision perturbative spectroscopy of heavy hadrons is limited by the leading
infrared renormalon of the static potential, which drives factorial growth in the
perturbative series and leaves a large residual dependence on the renormalization
scale. We present a renormalon-subtracted formulation of potential nonrelativistic
QCD, combining variational and Green's-function Monte Carlo...

23. Interacting quark matter under imaginary rotation

Tudor Pătuleanu (Institut Denis Poisson)

09/10/2026 10:50

Lattice QCD simulations with real rotation suffer from the sign problem, which can be avoided by introducing an imaginary angular velocity. Motivated by this, we study interacting quark matter in the linear sigma model under imaginary rotation, $\Omega = i\Omega_I$, and determine its thermodynamic properties and phase diagram. We show that the fractalization previously identified for free...

7. The dead cone effect across heavy-quark jet flavors

Dr Redamy PEREZ-RAMOS (IPSA/LPTHE)

09/10/2026 11:10

We present a unified overview of recent progress in the study of QCD radiation in heavy-quark jets, focusing on the dead-cone effect. Using precision data from LEP at ~91.2 GeV, we demonstrate strong momentum-space suppression in charm and bottom quark jets, supported by Monte Carlo simulations with Pythia8, and provide a quantitative interpretation within the Modified Leading Logarithmic...

39. Exploring the nucleon structure via Deeply Virtual Compton Scattering

Juan Sebastian Alvarado Galeano

09/10/2026 11:30

Generalized parton distributions (GPDs) are nucleon structure functions encoding longitudinal momentum and transverse position distributions of its constituent partons. In the zero-momentum-transfer limit ($t\rightarrow 0$), they provide access to fundamental mechanical and spin properties, in particular, the nucleon internal pressure distribution. Experimentally, GPDs can be probed through...

43. Flash talk

09/10/2026 11:50

44. Final Remarks

09/10/2026 12:05

24. EEC between two B hadrons inside bb-jets

Zoe Zaidan (CNRS - LLR)

The energy–energy correlator (EEC) has emerged as a precision jet substructure observable which separates the perturbative, confinement, and free hadron regimes of QCD along a single angular variable. We present a new measurement: computing the EEC between two reconstructed B hadrons inside bb-jets. This observable selects the g → bb topology, an antenna configuration with interesting and...

9. Fierz complete study of the NJL model in a rotating background

Andrea PALERMO

Nambu–Jona-Lasinio-type models are frequently employed as low-energy effective theories for fermionic systems and offer a powerful framework to analyse the structure of the phase diagram. The predictions from such models at finite rotation are of particular interest in the context of heavy-ion collisions, where a rotating Quark Gluon Plasma is created. In this work, we consider a...

17. Forward quarkonia production in pp and AA collisions at the ALICE experiment

Guilhem Baranger

One of the signatures of the Quark-Gluon Plasma (QGP), and its associated quark deconfinement, is the suppression of quarkonia production in heavy ions collisions due to the color screening effect.
With the addition of the Muon Forward Tracker (MFT) in Run 3, the ALICE experiment can now distinguish prompt from non-prompt quarkonia production at forward rapidity. The prompt component comes...

50. High-energy nuclear collisions: a new laboratory for many-body nuclear dynamics

Giuliano Giacalone

Relativistic nuclear collisions have emerged as a new laboratory for studying many-body correlations among nucleons in nuclear ground states. Focusing on ultra-central collisions, where nearly all nucleons participate, I will discuss how long-range nuclear correlations leave distinct imprints in final-state multi-particle correlation observables, and how scale separations inherent to the QCD...

5. Influence of the Gluon Mass on Non-Relativistic Tetraquark States

Sofia Bortagaray (UdelaR)

This poster presents a study of the spectrum of heavy tetraquarks within the Curci-Ferrari model, a low-energy effective framework for QCD in which gluons acquire an effective mass. Starting from the Curci-Ferrari Lagrangian, we derive an effective quark interaction potential and employ it to study heavy hadrons in the non-relativistic regime.

Tetraquarks are described within the...

35. Introduction to the 2026 AG GdR QCD

Audrey Francisco (CEA), M. Gines MARTINEZ (Subatech CNRS/IN2P3 - IMT Atlantique - Nantes Universite), Raphaël DUPRE, Savvas Zafeiropoulos (CPT Marseille, CNRS)

Few words to introduce the 2026 AG GdR QCD by the management team

41. Table Ronde : Prospectives GdR QCD

34. Welcome to Subatech

Pol-Bernard Gossiaux

Welcome of the Subatech Director

26. Yang-Mills theories with scalar matter: a first foray using the Curci-Ferrari model

GUSTAVO LEVY (CBPF)

The quantization of Yang–Mills (YM) theories via functional integrals requires gauge fixing, usually implemented through the Faddeev–Popov (FP) method. While successful at high energies due to asymptotic freedom, this framework fails in the infrared regime, where Gribov copies invalidate its assumptions. The Curci–Ferrari (CF) model addresses this issue by introducing a phenomenologically...