Conveners
Hadron Structure: (GPD) - Parallel 1
- Peter Pauli (University of Glasgow)
Hadron Structure: (TMD) - Parallel 1
- Andrew Puckett (University of Connecticut)
Hadron Structure: (Form Factors) - Parallel 1
- Daniel Lersch (Florida State University)
Hadron Structure: Parallel 1
- Volker Crede (Florida State University)
Hadron Structure: (Compton Scattering) - Parallel 1
- Sean Dobbs (Florida State University)
Hadron Structure: Parallel 1
- Maria Zurek (Argonne National Laboratory)
The quark-gluon dynamics manifests itself in a set of non-perturbative functions describing all possible spin-spin and spin-orbit correlations. Single and Dihadron semi-inclusive and hard exclusive production, both in current and target fragmentation regions, provide a variety of spin and azimuthal angle dependent observables, sensitive to the dynamics of quark-gluon interactions. Studies...
It is often taken for granted that Generalized Parton Distributions (GPDs) are defined in the "symmetric" frame, where the transferred momentum is symmetrically distributed between the incoming/outgoing hadrons. However, such frames pose more computational challenges for the lattice QCD practitioners. In this talk, we lay the foundation for lattice QCD calculations of GPDs in non-symmetric...
In this talk I will revisit the evolution of generalised parton distributions (GPDs) in momentum space.
I will present a recalculation of the evolution kernels in the MSbar scheme at one-loop accuracy, confirming previous results.
The kernels are arranged in a form suitable for numerical implementation allowing for an easy implementation in an existing open source code (APFEL++).
I will...
Generalized Parton Distributions (GPDs) are nowadays the object of an intense effort of research,
in the perspective of understanding nucleon structure. They describe the correlations between
the longitudinal momentum and the transverse spatial position of the partons inside the nucleon
and they can give access to the contribution of the orbital momentum of the quarks to the...
We present the most recent extraction of unpolarized transverse-momentum-dependent (TMD) parton distribution functions (PDFs) and TMD fragmentation functions (FFs) from global data sets of Semi-Inclusive Deep-Inelastic Scattering (SIDIS), Drell-Yan and Z boson production. The fit is performed at the N$^3$LL logarithmic accuracy in the resummation of q$_T$-logarithms and features flexible...
Semi-Inclusive Deep Inelastic Scattering on nuclei offers a new way to gain microscopic information about the mechanisms of parton propagation and hadron formation in QCD. The interactions with the nuclear medium of the partonic and hadronic participants in the hadronization process can reveal features of that process at the femtometer distance scale. New data from CLAS on baryon hadronization...
The thrust distribution associated with single-inclusive $e^+e^-$ annihilation (SIA$^{\text{thr}}$), sensitive to the transverse momentum of the detected hadron with respect to the thrust axis, represents one of the most challenging and promising case where to extend the TMD factorization beyond the standard processes. At present days, its factorization properties have been studied through two...
In the recent years, it has been realized that deep-inelastic scattering with polarization control could provide a variety of spin and azimuthal angle dependent observables sensitive to the quark-gluon interactions. New parton distributions and fragmentation functions have been introduced to describe the rich complexity of the hadron structure and move towards a multi-dimensional imaging of...
Elastic lepton-nucleon scattering is arguably the simplest measurable process sensitive to the nucleon's internal structure and dynamics. The spacelike and timelike electromagnetic form factors of the nucleon have been measured with ever increasing precision over a wide range of energies since the 1950's, and these measurements have led to many surprises and discoveries that changed our basic...
The JLab 12-GeV electron beam provides an opportunity to advance Q2 for all four electro-magnetic form-factors. Currently the results for GMp up to 15 GeV2 are published, and the data for GMn up to 13.5 GeV2 are collected. The Hall B GMn experiment also collected new data. In 2022-23 the GEn experiment will collect data for Q2 up 9.9 GeV2 and after that the data for GEp will be obtained up to...
Time-like hadron electromagnetic form factors are accessible through electron-positron annihilation into a hadron and anti-hadron pair and its time reverse reaction. Large progress was recently done at electron-positron colliders, applying the Initial State Radiation (ISR) method. Precise measurements of the proton form factor, up to s $simeq$ 40 GeV$2$, done by BaBar showed irregularities in...
Exploring the electromagnetic form factors of baryons helps us understand their internal structure and how the strong force binds the quarks together. The form factors of nucleons have been and continue to be studied extensively, but it is valuable to also pursue other, parallel avenues of research. A complementary and relatively unexplored approach is the study of hyperons. What does the...
Radiative transition of an excited baryon to a nucleon with emission of a virtual massive photon converting to dielectron pair (Dalitz decays) provides important information about baryon-photon coupling at low q2 in timelike region. These measurements are complementary to time like e+e- annihilation experiments at larger q2 value and meson production with electron and photon beams covering...
We consider the chiral Lagrangian with nucleon, isobar, and pion degrees of freedom. The baryon masses and the axial-vector form factor of the nucleon are derived at the one-loop level. We explore the impact of using on-shell baryon masses in the loop expressions. As compared to results from conventional chiral perturbation theory we find significant differences. An application to QCD lattice...
The spin content of the proton as a function of quark and gluon helicities and orbital angular momentum can be described in terms of integrals of parton distributions. These integrals, from x=0 to 1, require in particular a precise understanding of the asymptotic behavior of said distributions in the low x limit. We will discuss the resummation of double logarithms which governs this behavior...
In this talk we present our BK solution to next-to-leading order approach (NLO) and compare with the experimental HERA data. This approach includes the re-summed NLO corrections to the kernel of the evolution equation, the impact
parameter dependence of the saturation scale in accord with the Froissarrt theorem as well as the non-linear corrections. We successfully describe the...
An overview of the phenomenological aspects of generalized
parton distributions will be given, including recent results and fits
to available experimental data.
The Generalized Polarizabilities (GPs) are fundamental properties of the nucleon. They characterize the nucleon's response to an applied electromagnetic field, giving access to the polarization densities inside the nucleon. As such, they represent a central path towards a complete understanding of the nucleon dynamics. Previous measurements have challenged the theoretical predictions, raising...
Generalized Parton Distributions (GPDs) describe the correlations between the longitudinal momentum and the transverse position of the partons inside the nucleon. They are nowadays the subject of an intense effort of research, in the perspective of understanding nucleon spin and mechanical properties.
In this talk, we present the first observation of the Timelike Compton Scattering (TCS)...
The electromagnetic scalar polarizabilities ($\alpha$,$\beta$) are fundamental structure constants of the nucleon, and precise experimental measurements of these are vital for a complete understanding of the nucleonโs internal structure. The scalar polarizabilities can be accessed via Compton scattering reactions on light nuclei targets like $^1$H, $^2$H, and $^3$He. Such cross section...
Session: Hadron Structure
Author: Marie Boรซr, Virginia Tech
Abstract for contributed talk
Generalized Parton Distribution have been studied for many years and are a great tool to approach the multi-dimensional position vs momentum structure of the nucleon. Now, most of the measurements and constraints to GPD models are coming from DVCS (Deeply Virtual Compton Scattering). I will discuss...
Electromagnetic polarizabilities are fundamental properties of composite systems such as molecules, atoms, nuclei and hadrons. Polarizabilities measure the 'stiffness' of a system to electromagnetic deformation. Measurements of hadron polarizabilities provide a test of effective field theories, dispersion theories, and lattice calculations. While significant progress has been made in...
Both muon and hadron beams with a energy up to few hundred GeV are available at the M2 beamline of the CERN/SPS. AMBER (Apparatus for Meson and Baryon Experimental Research) is a new fixed-target experiment started in 2021. An ambitious experimental program of AMBER address the various aspects of the so-called Emergence of Hadron Mass mechanism: the charge radii of various hadrons, parton...
Electrons are much cleaner probes of nucleon structures than hadron beams. At the same time the electron scattering at large momentum transfer can be a source of considerable photon radiation, which can significantly distort the inferred nucleon structure if it is not properly accounted for. We present a factorized approach to semi-inclusive deep inelastic scattering, which treats QED and QCD...
Pion parton distribution functions (PDFs) have a long standing debate in QCD regarding the behavior of the valence quark PDF as the momentum fraction, $x$, approaches 1. Recently the Jefferson Lab Angular Momentum (JAM) collaboration has included both the historical fixed-target Drell-Yan (DY) data and the leading neutron (LN) electroproduction data from HERA in a simultaneous global QCD...
We reinterpret jet clustering as an axis-finding procedure which, along with the proton beam, defines the virtual-photon transverse momentum $q_T$ in deep inelastic scattering (DIS). In this way, we are able to probe the nucleon intrinsic structure using jet axes in a fully inclusive manner, similar to the Drell-Yan process. We present the complete list of azimuthal asymmetries and the...
In the present work, we have explored the higher twist T-even TMD $h_3$ in the light-front quark-diquark model. Within the same model, we have studied their relations with the leading twist TMDs and also calculated its average transverse momentum.
