Gluon Polarization In Nucleon

TL;DR

This paper uses the valon model to analyze gluon polarization in nucleons, revealing that the gluon contribution to nucleon spin can be significant despite a small measured ratio, emphasizing the importance of small-x behavior.

Contribution

It introduces a calculation of gluon polarization within the valon model, highlighting the potential for a sizable gluon contribution to nucleon spin despite small measured ratios.

Findings

The ratio δg/g is small and compatible with measurements.

The gluon polarization δg at small x can be large.

The first moment Δg(Q^2) of polarized gluons can be sizable.

Abstract

In the context of the so-called valon model, we calculate $\frac{\delta g}{g}$ and show that although it is small and compatible with the measured values, the gluon contribution to the spin of nucleon can be sizable. The smallness of $\frac{\delta g}{g}$ in the measured kinematical region should not be interpreted as $\delta g$ being small. In fact, $\delta g$ itself at small x, and the first moment of the polarized gluon distribution in the nucleon, $\Delta g(Q^2)$, are large