Gluon EMC effects in nuclear matter

TL;DR

This paper models the gluonic structure of nuclei using a mean-field approach based on the NJL model, revealing significant nuclear modifications of gluon distributions, termed the gluon EMC effect.

Contribution

It introduces a mean-field model that predicts sizeable gluon distribution modifications in nuclei, extending the EMC effect to gluons.

Findings

Significant nuclear modifications of gluon distributions in both unpolarized and polarized cases.

Prediction of a gluon EMC effect consistent with the nucleon structure modifications.

Extension of the EMC effect to include gluonic components in nuclear matter.

Abstract

We investigate the gluonic structure of nuclei within a mean-field model of nuclear structure based upon the modification of the structure of a bound nucleon, with the nucleon described by the Nambu--Jona-Lasinio model. This approach has been shown to reproduce the European Muon Collaboration (EMC) effect, involving the ratio of the spin-independent structure functions of a heavier nucleus to that of the deuteron. It also predicts a significant nuclear modification for the spin structure functions, known as the polarized EMC effect. Here we report sizeable nuclear modifications of the gluon distributions (a "gluon EMC effect") for the ratios of both the unpolarized and polarized gluon distributions in nuclear matter to those of a free nucleon.