On the behaviour of R(pA) at high energy

TL;DR

This paper analyzes the high-energy behavior of the ratio R(pA) of unintegrated gluon distributions in nuclei versus protons, revealing total gluon shadowing effects driven by fluctuations and Pomeron loops.

Contribution

It provides a theoretical analysis of R(pA) at high energy, highlighting the impact of gluon number fluctuations and Pomeron loops on gluon shadowing.

Findings

R(pA) increases with rapidity

Approaches 1/A^{1/3} at asymptotic rapidity

Indicates total gluon shadowing due to fluctuations

Abstract

We discuss the behaviour of R(pA), the ratio of the unintegrated gluon distribution of a nucleus over the unintegrated gluon distribution of a proton scaled up by A^{1/3}, at high energy and fixed coupling. We show that R(pA) exhibits a rising gluon shadowing with growing rapidity, approaching 1/A^{1/3} at asymptotic rapidity, which means total gluon shadowing due to gluon number fluctuations or Pomeron loops.