Conveners
QCD and hadron structure: Session 1
- Simone Marzani (Istituto Nazionale di Fisica Nucleare)
QCD and hadron structure: Session 2
- Eric Voutier (IN2P3)
QCD and hadron structure: Session 3
- Patrizia Rossi (Jefferson Lab)
QCD and hadron structure: Session 4
- Adam Hobart (IJCLab CNRS-IN2P3)
QCD and hadron structure: Session 5
- Maxime DEFURNE (CEA)
Lattice QCD has made tremendous progress both in the simulation of gauge ensembles as well as in the analysis of more challenging quantities that probe the 3D structure of hadrons like the generalised parton distributions (GPDs) but also in calculating quantities that potentially can reveal new physics, like the muon anomalous magnetic moment reaching a precision that matches the...
Generalized Parton distributions (GPDs) correlate the transverse position and the longitudinal momentum fraction of the partons in the nucleon. Over the last two and a half decades, there have been extensive studies of these distributions functions based on different exclusive lepton scattering reactions. The most established reactions are deeply virtual Compton scattering (DVCS), where a real...
Studies of nucleon resonance (N) electroexcitation amplitudes (gvpN electrocouplings) within a broad range of virtual photon four-momentum squared Q2 offer unique information on many facets of the strong interaction in the regime of large QCD running coupling (sQCD regime) seen in the generation of different resonances. The results on the gvpN* electrocouplings from exclusive meson...
In this talk, we present the numerical solution of the Schwinger-Dyson equation (SDE) for dynamical
quark masses and the homogeneous Bethe-Salpeter equation
for ground-state meson masses. Based on this analysis, we computed
the masses of light hadrons (pion, rho, and kaon) for a higher number of light quark flavors
$N_f$ and for a higher number of colors $N_c$. A...
A key step toward a better understanding of the nucleon structure is the study of Generalized Parton Distributions (GPDs). The particularity of GPDs is that they convey an image of the nucleon structure where the longitudinal momentum and the transverse spatial position of the partons inside the nucleon are correlated. Moreover, GPDs allow the quantification, via Ji's sum rule, of the...
The light-cone definition of Parton Distribution Functions (PDFs) does not allow for a direct ab initio determination employing methods of Lattice QCD simulations that naturally take place in Euclidean spacetime. In this presentation we focus on pseudo-PDFs where the starting point is the equal time hadronic matrix element with the quark and anti-quark fields separated by a finite distance. We...
Nucleon electroweak form factors contain relevant details about hadronic structure and strong interactions in the nonperturbative regime. This information is encoded in their dependence on the momentum transferred to the nucleon by external probes but also in their quark-mass dependence, which is accessible by Lattice QCD (LQCD) simulations.
In our study we rely on relativistic chiral...
The electromagnetic form factors (EMFFs) and the pair production cross sections of various baryons have been studied at BESIII, including the nucleon EMFFs and the hyperons. Anomalous enhancement behavior on the Lambda and Lambdac pair are observed. Besides, measurements on the SU(3) decuplet baryon have been
performed, such as Omega and Delta, and will be presented.
Next generation neutrino facilities, such as DUNE, rely on precise modelling of neutrino induced hadron knockout processes from nuclei in the detector medium (e.g Argon) to determine the initial (untagged) neutrino beam energy and determine the neutrino flux. However, uncertainty in the modelling of these nuclear interactions is currently the largest systematic uncertainty in extracting the...
to be added
We present a study of strong parity-violating contributions that can be included in inclusive Deep Inelastic Scattering (DIS) off an unpolarized proton target. We show that a non vanishing parity-violating structure function arise even in the case of pure photon exchange, in contrast with standard results.
The size of the additional strong parity-violating term is estimated by fitting...
We present a recursive quantum mechanical model for the polarized fragmentation process of a string stretched between a quark and an antiquark with entangled spin states. The quarks are assumed to be produced in the $e^+e^-$ annihilation process and are described by a joint spin density matrix that implements the correlations between their spin states. The string fragmentation process is...
The Electron Ion Collider (EIC) is a next-generation hadron physics facility, planned to be built in the coming decade at Brookhaven National Laboratory (BNL), with the intention of further exploring the quark and gluon substructure of hadrons and nuclei. The EIC will address fundamental questions in QCD, probing the interplay of quarks and gluons to learn how they contribute to overall...
J/ψ near threshold photoproduction plays a key role in the physics program at the Thomas Jefferson National Accelerator Facility (JLab) 12 GeV upgrade due to the wealth of information it has to offer. J/ψ photoproduction proceeds through the exchange of gluons in the t-channel and is expected to provide unique insight about the nucleon gluonic form factors and the nucleon mass radius.
The...
We study the leading twist gluon generalized parton distributions (GPDs) and the Wigner distributions of the gluons in the proton within a light-cone spectator model. The model provides an approach to generate the gluon degree of freedom from the proton target, in which the proton is regarded as a two-particle composite system composed of an active gluon ($g$) and a spectator particle ($uud$)....
The chiral anomaly is a fundamental property of quantum chromodynamics (QCD). It governs e.g. the decay of the neutral pion $\pi^0\to\gamma\gamma$. In general, it relates the coupling of an odd number of Goldstone bosons to vector bosons. In case of three pions, the magnitude of the resulting coupling is $F_{3\pi}$ and the value is precisely predicted by chiral perturbation theory. It can...
We propose a new way of studying the spin content of a hadron by looking at its response in a rotating frame. By collecting all responses of quarks and gluons in a rotating frame, we describe the spin-rotation coupling of spin-1 quarkonia and thereby reveal their spin contents in a fully relativistic way. We demonstrate that both the perturbative and non-perturbative contributions in the...
The internal structure of the nucleon is a field of intensive study. This structure can be experimentally probed through electron elastic scattering off a proton target. This allows the extraction of the proton electric and the magnetic form factors which characterize the charge and the magnetization densities. The spatial moments of the proton charge density are extracted using the electric...
What can we learn about the internal structure of hadrons from the matrix elements of the electromagnetic current and the energy-momentum tensor?
To give an answer we parametrize these matrix elements in terms of form factors and briefly discuss how the form factors are connected with experimentally measurable quantities, in particular the gravitational form factors with the generalized...
The Gravitational Form Factors (GFFs) give access to the internal distributions of mass, pressure and shear force inside the proton. They were considered experimentally unmeasurable for decades due to the very weak gravitational interaction [1]. However, the Generalized Parton Distributions (GPDs), which describe the correlations between the longitudinal momentum and the transverse position of...
Time-Like Compton Scattering (TCS) is a hard, exclusive scattering process, in which a real photon scatters from a target nucleon, producing a virtual
(timelike) photon, which couples to a lepton pair in the final state [1].
TCS, via cross section and asymmetry observables, gives access to Gener-
alised Parton Distributions (GPDs), through which we can develop a tomo-
graphic mapping of...
Accurate modelling of the b-jet fragmentation is important for measurements at the LHC where b-jets identification is required to isolate signal or reject backgrounds. In this talk, we present the measurement of b-quark fragmentation properties into jets using the decay of B hadrons to J/Psi and Kaon in pp collisions at the centre-of-mass energy of 13 TeV. In addition, charged-particle...
