Classical Gluon Production Amplitude for Nucleus-Nucleus Collisions: First Saturation Correction in the Projectile

TL;DR

This paper derives a leading-order gluon production amplitude in nucleus-nucleus collisions, incorporating the first saturation correction in the projectile nucleus while resumming all saturation effects in the target.

Contribution

It introduces the first analytic calculation of the projectile saturation correction to gluon production in nucleus-nucleus collisions, advancing understanding of saturation effects.

Findings

Calculated the order-g^3 single-gluon production amplitude including projectile saturation correction.

Resummed all saturation corrections in the target nucleus.

Provided a foundational step towards full analytic expressions for gluon production cross sections.

Abstract

We calculate the classical single-gluon production amplitude in nucleus-nucleus collisions including the first saturation correction in one of the nuclei (the projectile) while keeping multiple-rescattering (saturation) corrections to all orders in the other nucleus (the target). In our approximation only two nucleons interact in the projectile nucleus: the single-gluon production amplitude we calculate is order-g^3 and is leading-order in the atomic number of the projectile, while resumming all order-one saturation corrections in the target nucleus. Our result is the first step towards obtaining an analytic expression for the first projectile saturation correction to the gluon production cross section in nucleus-nucleus collisions.