Valence Quark Polarization In the Nucleon And the Deuteron Data

Abstract

Within the framework of the so-called "valon" model, we argue that a substantial part of the nucleon spin, about 40%, is carried by the polarized valence quarks. The remaining is the result of cancellations between gluon polarization and the orbital angular momentum, where the gluon polarization is the dominant one. It is shown that the sea quark contribution to the spin of any hadron is simply marginal and consistent with zero. Our findings point to a substantially smaller value for a_8 thaninferred from hyperon- $\beta$ decay, suggesting that fullSU(3) symmetric assumption needs to be reconsidered. New and emerging experimental data tend to support this finding. Finally, we show that within the model described here the experimental data on the polarized structure functions $g_1^{p,n,d}$ are reproduced.

12 pages, 5 figures To appear in Phys. Lett. B

References in corpus (15)

• Precise determination of the spin structure function ${\mathbf{g}}_1$ of the proton, deuteron and neutron
• The Deuteron Spin-dependent Structure Function g1d and its First Moment
• Quark helicity distributions in the nucleon for up, down, and strange quarks from semi--inclusive deep--inelastic scattering
• The Spin Structure of the Nucleon in the Asymptotic Limit
• Flavor decomposition of the sea quark helicity distributions in the nucleon from semi-inclusive deep-inelastic scattering
• Sea quark and gluon polarization in the nucleon at NLO accuracy
• Spin Contents of Nucleons with SU(3) Breaking
• Spin-dependent non-singlet structure functions in next-to-leading order
• Next-to-Leading Order Constituent Quark Structure and Hadronic Structure Functions
• Pion Structure Function $F_2^{\pi }$ in the Valon Model
• How to Use Weak Decays in Analyses of Data on Nucleon Spin Structure Functions
• Meson Structure Functions in Valon Model
• Polarized Structure of Nucleon in the Valon Representation
• Note on Strange Quarks in the Nucleon
• Measurement of $\Delta S$ in the nucleon at HERMES from semi-inclusive DIS

Cited by in corpus (4)

• Transversity Distribution Functions in the Valon Model
• Non-Singlet spin structure function in the valon model and low x scaling behavior of $g_1^{NS}$ and $g_1^p$
• Gluon Polarization In Nucleon
• Transverse Spin Structure Function g2(x, Q2 ) in the Valon model