Classical initial conditions in high energy nucleus-nucleus collisions

TL;DR

The paper introduces an iterative method to compute classical gauge fields in high-energy nucleus collisions, providing a simple gluon production formula at leading order, but noting the breakdown of $k_t$-factorization.

Contribution

It presents a new iterative approach for calculating classical gauge fields and gluon production in nucleus collisions, highlighting limitations of existing factorization methods.

Findings

Derived a simple formula for gluon production at leading order

Identified the breakdown of $k_t$-factorization at this order

Proposed an iterative procedure for classical field computation

Abstract

An iterative proceedure is proposed to compute the classical gauge field produced in the collision of two heavy nuclei at high energy. The leading order is obtained by linearizing the Yang-Mills equations in the light-cone gauge, and provides a simple formula for gluon production in nucleus-nucleus collisions. At this order $k_t-$factorization breaks down.