Related papers: Factorization Scheme and Parton Distributions in t…
Data on the nucleon spin structure suggests that the $u$ (and $d$) quark distributions in the $\Lambda$ hyperon may be polarized. If this correlation carries over into fragmentation, then the study of polarized $\Lambda$'s in the current…
We have analyzed the beam spin asymmetry and the longitudinally polarized target spin asymmetry of the Deep Virtual Compton Scattering process, recently measured by the Jefferson Lab CLAS collaboration. Our aim is to extract information…
We develop the analysis of diphoton exclusive photoproduction in the kinematics where a collinear QCD factorization framework applies, namely nearly forward large invariant mass diphoton production. We work at the leading twist level and at…
We present pion and kaon parton distribution functions from a global QCD analysis of the experimental data within the framework of dynamical parton model. We use the DGLAP equations with parton-parton recombination corrections and the…
The main focus of the physics program at PHENIX and STAR that makes use of RHIC's polarized proton beams is to figure out how and if at all the gluons inside protons are polarized, or to put it another way, do the spin 1 gluons prefer to…
We study parton distributions for two partons, a quark and a gluon, in the light-front dressed quark model, with focus on correlations between the two partons. The model calculation leads to sizable spin-spin and spin-kinematic correlations…
Parton distributions encode the momentum-space structure and, in their generalizations, the spatial tomography of quarks and gluons inside hadrons, the building blocks of visible matter. We present a unified neural-network approach that…
We consider the azimuthal angle dependence in the cross section of the hard leptoproduction of a photon on a nucleon target. We show that this dependence allows to define observables that isolate the twist-two and twist-three sectors in the…
Spin and polarization are central to precision tests of fundamental physics and for interpreting radiation from astrophysical sources and ultraintense laser-matter experiments. Predictive modeling therefore requires not only energy spectra,…
Global perturbative QCD analyses, based on large data sets from electron-proton and hadron collider experiments, provide tight constraints on the parton distribution function (PDF) in the proton. The extension of these analyses to nuclear…
We present the results of a complete leading-twist next-to-leading order (NLO) QCD analysis of the spacelike pion electromagnetic form factor at large momentum transfer Q. We have studied their dependence on the form of the pion…
This work focuses on applications of perturbative QCD (pQCD) and collinear factorization theorem to hard particle production in nuclear and hadronic collisions at the BNL-RHIC and CERN-LHC colliders. The emphasis is on nuclear parton…
We investigate unpolarized and polarized gluon distributions and their applications to the Ioffe-time distributions, which are related to lattice QCD calculations of parton distribution functions. Guided by the counting rules based on the…
Sets of parton distribution functions (PDFs) of the proton are reported for the leading (LO), next-to-leading (NLO) and next-to-next-to leading order (NNLO) QCD calculations. The parton distribution functions are determined with the…
We consider the hard leptoproduction of a photon off nuclei up to spin-1. As a new result we present here the general azimuthal angular dependence of the differential cross section for a spin-1 target. Its twist-two Fourier coefficients of…
Using continuum Schwinger function methods, a coherent set of predictions for proton, $\Lambda$ and $\Sigma^0$ distribution functions (DFs) has been made available -- both helicity dependent and unpolarised. The results and comparisons…
Effects of the spin-dependent gluon distributions on J/$\psi$ productions in polarized ep and pp collisions are investigated. These productions serve as a very clean probe of the spin-dependent gluon distributions in a proton.
Parameter-free and perturbatively stable leading order (LO) and next-to-leading order (NLO) parton densities for real and virtual photons are presented.
Applications of perturbative QCD to deeply virtual Compton scattering process require a generalization of usual parton distributions for the case when long-distance information is accumulated in nonforward matrix elements of quark and gluon…
We review the current status of Parton Distribution Function (PDF) determinations for unpolarized and longitudinally polarized protons and for unpolarized nuclei, which are probed by high-energy hadronic scattering in perturbative Quantum…