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Title: PARTON DISTRIBUTIONS AND SPIN-ORBITAL CORRELATIONS.

Abstract

In this talk, the author summarizes a recent study showing that the large-x parton distributions contain important information on the quark orbital angular momentum of nucleon. This contribution could explain the conflict between the experimental data and the theory predictions for the polarized quark distributions. Future experiments at JLAB shall provide further test for our predictions.

Authors:
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
922237
Report Number(s):
BNL-79723-2007-CP
R&D Project: 81128; KB-02-01; TRN: US0801023
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Conference
Resource Relation:
Conference: WORKSHOP AT JLAB - PROCEEDINGS OF EXCLUSIVE REACTIONS AT HIGH MOMENTUM TRANSFER; NEWPORT NEWS, VA; 20070521 through 20070523
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; MOMENTUM TRANSFER; ORBITAL ANGULAR MOMENTUM; QUARKS

Citation Formats

FENG,Y. PARTON DISTRIBUTIONS AND SPIN-ORBITAL CORRELATIONS.. United States: N. p., 2007. Web.
FENG,Y. PARTON DISTRIBUTIONS AND SPIN-ORBITAL CORRELATIONS.. United States.
FENG,Y. Mon . "PARTON DISTRIBUTIONS AND SPIN-ORBITAL CORRELATIONS.". United States. doi:. https://www.osti.gov/servlets/purl/922237.
@article{osti_922237,
title = {PARTON DISTRIBUTIONS AND SPIN-ORBITAL CORRELATIONS.},
author = {FENG,Y.},
abstractNote = {In this talk, the author summarizes a recent study showing that the large-x parton distributions contain important information on the quark orbital angular momentum of nucleon. This contribution could explain the conflict between the experimental data and the theory predictions for the polarized quark distributions. Future experiments at JLAB shall provide further test for our predictions.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 21 00:00:00 EDT 2007},
month = {Mon May 21 00:00:00 EDT 2007}
}

Conference:
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  • In this talk, I summarize a recent study showing that the large-x parton distributions contain important information on the quark orbital angular momentum of nucleon. This contribution could explain the conflict between the experimental data and the theory predictions for the polarized quark distributions. Future experiments at JLab shall provide further test for our predictions.
  • New data from the European Muon Collaboration (EMC) on the spin-spin asymmetry in deep-inelastic lepton-proton scattering suggests that the total spin carried by valence quarks in a polarized proton may be approximately canceled by a strong negative polarization of the sea of q-barq pairs. The evolution in Q/sup 2/ of the fraction of proton spin carried by gluons depends on the initial spin fractions and it is possible to avoid the introduction of large orbital angular momentum by adopting a ''hybrid'' quark-Skyrme picture of the proton suggested by the EMC results.
  • The case for parton orbital angular momentum is considered in the light of the EMC data. 8 figs.
  • We present a lattice measurement of the first two moments of the spin-dependent GPD H-tilde(x,xi,t). From these we obtain the axial coupling constant and the second moment of the spin-dependent forward parton distribution. The measurements are done in full QCD using Wilson fermions. In addition, we also present results from a first exploratory study of full QCD using Asqtad sea and domain-wall valence fermions.
  • Spin-dependent quark light-cone momentum distributions are calculated for a nucleon in the nuclear medium. We utilize a modified NJL model where the nucleon is described as a composite quark-diquark state. Scalar and vector mean fields are incorporated in the nuclear medium and these fields couple to the confined quarks in the nucleon. The effect of these fields on the spin-dependent distributions and consequently the axial charges is investigated. Our results for the ''spin-dependent EMC effect'' are also discussed.