Related papers: Polarized Parton Distributions: Theory and Experim…
Statistical approach for proton and neutron have been used to study the low energy properties of nucleons. Nucleons is assumed as a composite system of three quarks and "sea" where sea is assumed to be in S-wave consisting of…
It is shown that in both the gluonic and strange sea explanations of the Ellis-Jaffe sum rule violation discovered by the European Muon Collaboration (EMC), the spin of the proton, when viewed in in its rest reference frame, could by fully…
We discuss the latest CCFR determination of the strange sea density of the proton. We comment on the differences with a previous, leading--order, result and point out the relevance of quark mass effects and current non--conservation…
Starting from Martin, Roberts and Stirling fit for unpolarized deep inelastic structure functions and using the newest experimental data on spin asymmetries we get a fit which provides polarized quark distributions. We analyze the behaviour…
Effect of the quark intrinsic motion on the proton spin structure functions is demonstrated. It is shown, that the covariant version of the quark-parton model taking into account the orbital motion gives the consistent picture of the proton…
We investigate the possibility to draw conclusions on the sign of the spin-dependent gluon distribution, $\Delta G(x, Q^2)$, from existing polarized DIS data. The spin-dependent parton distributions $\Delta u_v, \Delta d_v, \Delta {\bar u},…
We treat the baryon as a composite system made out of a \lq\lq core" of three quarks (as in the standard quark model) surrounded by a \lq\lq sea" (of gluons and $q\bar{q}$-pairs) which is specified by its total quantum numbers like flavor,…
I review the current status of the determination of helicity-dependent, or polarized, parton distribution functions from a comprehensive analysis of experimental data in perturbative quantum chromodynamics. I illustrate the latest…
Taking proton as an ensemble of quark-gluon Fock states and using the principle of detailed balance, we construct a simple statistical model for parton distribution of proton. The recent observed Bjorken-$x$ dependent light flavor sea quark…
We propose to use Fermi-Dirac distributions for quark and antiquark partons. It allows a fair description of the $x$-dependence of the very recent NMC data on the proton and neutron structure functions $F_2^p(x)$ and $F_2^n(x)$ at $Q^2=4$…
Although the distributions of sea quarks and antiquarks generated by leading-twist QCD evolution through gluon splitting $g \rightarrow \bar q q$ are necessarily CP symmetric, the distributions of nonvalence quarks and antiquarks which are…
The strange sea quarks distributions of nucleons obtained by two global analyses based on available structure function data of muon and neutrino deep inelastic scatterings are different from the strange sea quark distribution measured by…
Using DGLAP evolution equation with the corrections of parton recombinations, the flavor asymmetric sea quark distributions in the proton are first extracted from the available experimental data with the global QCD analysis method.…
We evaluate the gluon and quark contributions to the spin of the proton using an ensemble of gauge configuration generated at physical pion mass. We compute all valence and sea quark contributions to high accuracy. We perform a…
We investigate the sea quark polarization in the nucleon by means of a combined next to leading order analysis to the recently enlarged set of inclusive and semi-inclusive polarized deep inelastic scattering data. Using the Lagrange…
We present a critical assessment of what can be learnt from the present data on inclusive polarized DIS. We examine critically some of the simplifying assumptions made in recent analyses and study in detail the question of the determination…
This talk reviews some of the hot topics in spin physics and related subjects, including perturbative QCD predictions for polarized parton distributions and their possible behaviours at small x, the Bjorken and singlet sum rules and the…
The STAR experiment at RHIC is carrying out a comprehensive high-energy spin physics program to understand the internal structure and dynamics of the proton in polarized proton-proton collisions at $\sqrt{s} = 200$ GeV and $\sqrt{s} =…
The use of weak decays to determine proton spin structure is examined in view of possible violations of the Bjorken and Gottfried Sum rules, flavor symmetry breaking and flavor asymmetry in the sea. The use of the neutron decay is found to…
Some very unusual features of the hadron structure functions, obtained in the generalized QCD sum rules, like the surprisingly strong difference between longitudinally and transversally polarized $\rho$ mesons structure functions and the…