Polarized Nucleon Structure Functions within a Chiral Soliton Model

Abstract

We study polarized-spin structure functions of the nucleon within the bosonized Nambu-Jona-Lasinio model where the nucleon emerges as a chiral soliton. We present the electromagnetic polarized structure functions, $g_{1}(x)$ and $g_{2}(x)$ for $ep$ scattering and discuss various sum rules in the valence quark approximation. This approximation is justified because in this model axial properties of the nucleon are dominated by their valence quark contributions. We find that these structure functions are well localized in the interval $0\le x \le1$. We compare the model predictions on the polarized structure functions with data from the E143 experiment by evolving them from the scale characteristic of the NJL-model to the scale of the data. Additionally a comparison is made with parameterized data at a momentum scale commensurate with the model calculation.