CGC for Ultra-Peripheral Pb+Pb Collisions at the Large Hadron Collider: a more realistic calculation

TL;DR

This paper presents the first calculation of two-gluon production in ultra-peripheral Pb+Pb collisions at the LHC within the Color Glass Condensate framework, comparing different photon wave function models to estimate uncertainties.

Contribution

It introduces a realistic calculation of two-gluon production in ultra-peripheral collisions using two photon wave function models within the CGC framework.

Findings

Two-gluon correlation functions were successfully extracted.

Azimuthal harmonics were computed for the first time in this context.

The target nucleus can be approximated as a highly saturated state.

Abstract

We provide the first calculation of two-gluon production at mid-rapidity in ultra-peripheral collisions in the Color Glass Condensate framework. To estimate systematic uncertainty associated with poor understanding of the wave function of the nearly real photon, we consider two diametrically different models: the dilute quark-antiquark dipole approximation and a vector meson, in which color charge density is approximated by McLerran-Venugopalan model. In the experimentally relevant range, the target nucleus can be faithfully approximated by a highly saturated state. This simplification enables us to perform efficient numerical simulations and extract the two-gluon correlation functions and the associated azimuthal harmonics.