Gluon Sivers function in a light-cone spectator model

TL;DR

This paper models the gluon Sivers function in a proton using a light-cone spectator approach, fitting parameters to known data, and finds results consistent with recent phenomenological extractions and sum rule constraints.

Contribution

It introduces a light-cone spectator model with gluon degrees of freedom to calculate the gluon Sivers function in the valence-x region.

Findings

Results agree with recent phenomenological extractions.

Estimated gluon transverse momentum aligns with the Burkardt sum rule.

Model parameters fitted to known gluon density distributions.

Abstract

We calculate the gluon Sivers function of the proton in the valence-$x$ region using a light-cone spectator model with the presence of the gluon degree of freedom. We obtain the values of the parameters by fitting the model resulting gluon density distribution to the known parametrization. We find that our results agree with the recent phenomenological extraction of the gluon Sivers function after considering the evolution effect. We also estimate the mean transverse momentum of the gluon in a transversely polarized proton and find that it is within the range implied by the Burkardt sum rule.