Evolution of initial stage fluctuations in the glasma

TL;DR

This paper analytically studies the evolution of fluctuations in the energy density and axial charge in the early glasma stage of heavy ion collisions, using linearized Yang-Mills equations and the McLerran-Venugopalan model.

Contribution

It introduces a systematic method to resum high momentum mode contributions and provides analytical insights into the preequilibrium phase of heavy ion collisions.

Findings

Analytical expressions for correlation functions at finite proper time.

Resummation technique for high momentum modes.

Application of the approach to general four-point functions.

Abstract

We perform a calculation of the one- and two-point correlation functions of energy density and axial charge deposited in the glasma in the initial stage of a heavy ion collision at finite proper time. We do this by describing the initial stage of heavy ion collisions in terms of freely evolving classical fields whose dynamics obey the linearized Yang-Mills equations. Our approach allows us to systematically resum the contributions of high momentum modes that would make a power series expansion in proper time divergent. We evaluate the field correlators in the McLerran-Venugopalan model using the glasma graph approximation, but our approach for the time dependence can be applied to a general four-point function of the initial color fields. Our results provide analytical insight into the preequilibrium phase of heavy ion collisions without requiring a numerical solution to the Yang-Mills equations.