The Intrinsic Glue Distribution at Very Small x

TL;DR

This paper extends the McLerran-Venugopalan model to compute gluon distribution functions at very small x, revealing a Lipatov-like enhancement and addressing unitarity in lepton-nucleus interactions.

Contribution

It introduces a renormalization group extension of the model to describe gluon distributions at smaller x and includes transverse momentum dependence.

Findings

Identifies a Lipatov-like enhancement in gluon distributions.

Provides estimates for transverse momentum dependence.

Shows how unitarity is maintained in lepton-nucleus interactions.

Abstract

We compute the distribution functions for gluons at very small x and not too large values of transverse momenta. We extend the McLerran-Venugopalan model by using renormalization group methods to integrate out effects due to those gluons which generate an effective classical charge density for Weizs\"acker-Williams fields. We argue that this model can be extended from the description of nuclei at small x to the description of hadrons at yet smaller values of x. This generates a Lipatov like enhancement for the intrinsic gluon distribution function and a non-trivial transverse momentum dependence as well. We estimate the transverse momentum dependence for the distribution functions, and show how the issue of unitarity is resolved in lepton-nucleus interactions.