A spectator-model way to transverse-momentum-dependent gluon distribution functions

TL;DR

This paper explores the three-dimensional gluon structure of the proton using a spectator model to analyze unpolarized and polarized gluon TMDs, aiding future experimental investigations.

Contribution

It introduces a flexible spectator-model approach to calculate gluon TMDs, accommodating both moderate and small-x effects, advancing the understanding of gluon dynamics inside nucleons.

Findings

Provides a new parametrization for gluon TMDs

Offers insights into gluon behavior at different x regimes

Guides future experimental studies of gluon structure

Abstract

We present exploratory analyses of the 3D gluon content of the proton via a study of unpolarized and polarized gluon TMDs at twist-2, calculated in a spectator model for the parent nucleon. Our approach embodies a flexible parametrization for the spectator-mass function, suited to describe both moderate and small-$x$ effects. All these studies can serve as a useful guidance in the investigation of the gluon dynamics inside nucleons and nuclei, which constitutes one of the major goals of new-generation colliding machines, as the EIC, the HL-LHC, NICA, and the FPF.