Selected aspects of hadron physics that will be accessible at higher beam energies at JLab will be discussed. Possible solutions to precision particle tracking and the expansion of electron and photon detection to larger polar angles will be discussed.
We discuss the new physics which can be accessed with doubling the energies of CEBAF accelerator at Jefferson Lab. This relates to probing three-nucleon short range correlations in nuclei and measuring deep-inelastic nuclear structure at $x>1$ that will allow for the first time to probe the dynamics responsible for generation of super-fast quarks in nuclei. Other venues of research is the...
We investigate φ meson photoproduction on the nucleon and 4He targets within a dynamical model approach based on a Hamiltonian which describes the production mechanisms by the Pomeron exchange, meson exchange, φ radiation, and nucleon resonance excitation mechanisms. The final φN interactions are included and described by the gluon-exchange, direct φN couplings, and the box diagrams. Our...
In this talk, I will present an overview on the transverse momentum dependent parton distribution: current status and future perspectives.
The transverse-momentum-dependent parton distributions (TMDs) are key quantities that describe the 3D proton structure seen in high-energy scatterings. The TMDs can be extracted from hard processes where a TMD factorization formula applies, while the key challenges faced by global analyses include the non-perturbative effects when the parton transverse momentum is at the QCD scale...
Nucleon spin structure studies at COMPASS: recent results and prospects COMPASS is a fixed target high energy physics experiment located at the M2 beamline (SPS, North Area) at CERN. The experiment is collecting data since 2002 covering a broad range of physics topics. Experimental results obtained by COMPASS during phase-I (2002-2011) for spin (in)dependent azimuthal azimuthal effects in...
I will present the scientific case of the solenoidal large intensity device (SoLID) using the 12 GeV upgrade of Jefferson Lab with the three pillar experiments, namely, the semi-inclusive deep inelastic scattering (SIDIS), the parity violation deep inelastic scattering (PVDIS), and the near-threshold J/psi production. I will also discuss the unique scientific reach, not presently accessible, a...
Measurements in SIDIS provide a wide range of insights into nucleon structure and hadronization. Recent measurements of beam spin asymmetries of $\pi^+\pi^-$ dihadron production at CLAS provide the first opportunity to extract $e(x)$, a collinear twist-3 distribution function. Ongoing and future experiments at 12 GeV will grant access to other collinear twist-3 distributions, such as...
During the Eg2 run, the CLAS detector collected experimental data on a wide range of nuclear targets, including a nucleus as heavy as Lead and as light as Carbon or Deuterium. These data allowed us to study various aspects of the nuclear hadronization process, nuclear color transparency, short-range nuclear collations, two-pion correlations, and others. In particular, varying sizes of nuclei...
New physics frontiers can be opened by using internal gas targets at the LHC. The various collision systems like pp, pA, and PbA at energies varying from √s_NN=72 GeV to √s=115 GeV, and the implicit forward kinematic of the collisions, make accessible a broad program of measurements, from the large-$x$ frontier for particle and astroparticle physics to spin and heavy-ion physics. A first step...
Fracture functions describes the hadron production in the target fragmentation region in the hard processes, namely -- the spin and transverse momentum dependent correlations between struck parton in the target and hadron production from target remnant. In this talk I'll shortly describe the leading order formalism and present the theoretical results for SIDIS and Drell-Yan processes. New...
The study of the properties of hadrons produced in the target fragmentation region (TFR) serve as a test of our complete understanding of the production mechanisms in SIDIS and provide additional information on QCD dynamics that are not accessible in the current fragmentation region (CFR). We report first results for a number of TFR sensitive measurements that can be interpreted in terms of...
Various nonperturbative aspects of quantum chromodynamics share a common feature combining orbital angular momentum with coherence at a hadronic scale. Nonperturbative fluctuations involving triplet P-zero quark-antiquark pairs play a significant role in the isospin structure of proton sea, in the flux-rupture of the Collins function, and in the nonperturbative final-state interaction leading...
In the target fragmentation region of Semi-Inclusive Deep Inelastic Scattering, the diffractively produced hadron has small transverse momentum. If it is at order of $\Lambda_{\rm QCD}$, it prevents to make predictions with the standard collinear factorization. However, in this case, differential cross-sections can be predicted by the factorization with fracture functions, diffractive parton...
I discuss a theoretical simulation of the virtual meson production amplitude in the forward direction using a simple scalar field model. Taking advantage of the light-front dynamics in 1+1 dimensions, I present the analysis of all the contributions including both “handbag” and “cat’s ears” for the entire kinematic regions of $Q^2>0$ and $t<0$ in the one loop level. The result from the GPD...
Radiative corrections to polarized SiDIS are calculated exactly and within the leading log approximation. Analytical and numerical comparisons of RC in both approaches as well as the results of other groups are presented and discussed. The contribution of exclusive radiative tail for polarized initial particles are estimated for the first time. Numerical analysis is performed in the frame of...
We present our recent study on the light-quark distribution functions in a heavy baryon within the chiral quark-soliton model. We mainly consider the twist-2 isoscalar unpolarized and isovector longitudinally polarized quark distributions which are large in the limit $N_c \to \infty$. We discuss the sum rules and the behavior of the x-dependences of the distributions when the heavy-quark mass...
We discuss the deeply virtual meson production in the (1+1)-dimensional scalar field model. To describe the scattering process, two approaches, the one-loop approximation and the leading twist of the scalar loop, are considered for the scalar meson production off the charged scalar target, e.g., $\gamma^{*} + {}^{4}{\rm He} \to f_{0}(980) + {}^{4}{\rm He}$. We particularly focus on the...
The generalized Parton distributions for the Goldstone boson are investigated in the framework of the quark chiral effective theory. Interesting results for the form factor and Parton distribution functions of the Goldstone boson as well as the Goldstone boson's 3D tomography picture will be presented and discussed.
We make a calculation for polarized vector meson production SIDIS by considering the general case of neutral current electroweak interactions. We present a kinematic analysis for the process and show that the cross section is expressed by 81 structure functions. We further make a QCD parton model calculation at the leading twist and give the structure functions results in terms of the...
Being motivated mainly by the LHC physics, the currently used Monte Carlo Event Generators (MCEGs) lack of the quark spin degree of freedom in their hadronization models, and can not reproduce observed transverse spin effects such as the Collins and the dihadron asymmetries, and longitudinal spin effects such as the jet handedness. To guide the interpretation of SIDIS and $e^+e^-$ data as well...
I present a general discussion on peculiarities of analysis of SIDIS data within the TMD factorization approach. The special emphasis is made on the features of the low-energy experiments and correlation between various ingredients of the TMD framework.
Nucleon-to-meson Transition Distribution Amplitudes (TDAs) appear as building blocks in the collinear factorized description of amplitudes for a class of hard exclusive reactions prominent examples being hard exclusive pion electroproduction off a nucleon in the backward region and nucleon-antinucleon annihilation into a pion and a lepton pair.
We discuss general properties of...
Generalized Parton Distribution (GPDs) functions describe the correlation between the spatial distribution of the quarks and their longitudinal momentum fraction. Their definition in the mid-1990s has revolutionized our approach to the description of the internal structure of the nucleon. The study of the GPDs, together with the study of similar quantities, are at the forefront of today...
Generalized parton distributions (GPDs) are important quantities that characterize the structure of hadrons. They provide information about the partons’ momentum distribution and also on their distribution in position space. Most of the information from lattice QCD is on the Mellin moments of GPDs, namely form factors and their generalizations. Recent developments in calculations of matrix...
The measurements of deeply virtual exclusive electroproduction processes are used to access and constrain the Generalized Parton Distributions from experimental observables. Among these exclusive reactions, deeply virtual meson production (DVMP) channels can be used to access chiral-even and chiral-odd GPDs which contain information about correlations between quark longitudinal momentum and...
We discuss recent developments in the field of generalised parton distributions (GPDs) obtained with the PARTONS framework (https://partons.cea.fr). This includes in particular addressing the problem of model dependency, which spoils both the modelling of GPDs, and the extraction of quantities like D-term and amplitudes of exclusive processes. A bunch of other recent results, and a new Monte...
A key step toward a better understanding of the nucleon structure is the study of Generalized Parton Distributions (GPDs). GPDs are nowadays the object of an intense effort of research since 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 give access, via Ji's sum...
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...
The emergence of hadron mass (EHM) represents one of the most challenging and still open problem in the Standard Model. New opportunities to shed light on EHM from the studies of the nucleon resonance electroexcitation amplitudes (or $g_vpN^*$ electrocouplings) in the range of photon virtualities $Q^2<35$ GeV$^2$ from the measurements of exclusive meson electroproduction with a detector...
The structure of the pion is studied within a dynamical model of the Bethe-Salpeter amplitude with dressed gluon exchange and constituent quarks [1]. The model reproduces the pion charge form-factor [2] and also provides the valence quark PDF, which is also compared to existing models and experimentally extracted PDF's [3]. Also results for some of the transverse momentum distributions will be...
