# Valence Quark Polarization In the Nucleon And the Deuteron Data - High Energy Physics - Phenomenology

Abstract: Within the framework of the so-called -valon- model, we argue that asubstantial part of the nucleon spin, about 40%, is carried by the polarizedvalence quarks.
The remaining is the result of cancellations between gluonpolarization and the orbital angular momentum, where the gluon polarization isthe dominant one.
It is shown that the sea quark contribution to the spin ofany hadron is simply marginal and consistent with zero.
Our findings point to asubstantially smaller value for a 8 thaninferred from hyperon- $\beta$ decay,suggesting that fullSU3 symmetric assumption needs to be reconsidered.
Newand emerging experimental data tend to support this finding.
Finally, we showthat within the model described here the experimental data on the polarizedstructure functions $g {1}^{p,n,d}$ are reproduced.

Author: Firooz Arash, Fatemeh Taghavi-Shahri

Source: https://arxiv.org/