Re-examining valence quark spin distributions

Abstract

The observed deep inelastic nucleon spin asymmetries $A_1^{p,n}$ and the spin dependent quark distributions break SU(6) spin - flavour symmetry. In quark models two mechanisms for breaking SU(6) symmetry are well known: the hyperfine interaction and the pion cloud of the nucleon. I re-evaluate these mechanisms and show how the breaking of SU(6) in each case affects spin dependent valence quark distributions of the proton. In particular I investigate the properties of these mechanisms in the kinematic region $0.3<x<0.7$ and attempt to test these against known data. Both mechanisms are able to explain the quantitative features of the spin asymmetries.

27 pages, 6 figures. Revised version accepted for publication in Physical Review D

References in corpus (4)

• Constraints on large-$x$ parton distributions from new weak boson production and deep-inelastic scattering data
• Inclusive cross section and double helicity asymmetry for π^0 production in p+p collisions at sqrt(s)=200 GeV: Implications for the polarized gluon distribution in the proton
• Measurement of the electron charge asymmetry in $\mathbf{p}\bar{\mathbf{p}}\to \mathbf{W}+\mathbf{X}\to \mathbf{e\nu }+\mathbf{X}$ decays in $\mathbf{p}\bar{\mathbf{p}}$ collisions at $\sqrt{\mathbf{s}}=1.96$ TeV
• Resolution of the Proton Spin Problem

Cited by in corpus (2)

• The Spin Structure of the Nucleon
• Transverse Momentum and Transverse Momentum Distributions in the MIT Bag Model