The first fermi in a high energy nuclear collision

TL;DR

This paper investigates the initial gluon production in high-energy nuclear collisions using non-perturbative methods, revealing a relation between energy and number densities tied to the saturated parton density.

Contribution

It introduces a non-perturbative relation at formation time linking energy and number densities to the saturated parton density in the nucleus.

Findings

Partons are on shell after formation time.

A simple relation exists between energy and number densities.

The scale is determined by the saturated parton density.

Abstract

At very high energies, weak coupling, non-perturbative methods can be used to study classical gluon production in nuclear collisions. One observes in numerical simulations that after an initial ``formation'' time, the produced partons are on shell, and their subsequent evolution can be studied using transport theory. At the initial formation time, a simple non-perturbative relation exists between the energy and number densities of the produced partons, and a scale determined by the saturated parton density in the nucleus.