# Effective kinetic description of the expanding overoccupied Glasma

## TL;DR

This study numerically investigates the kinetic evolution of an overoccupied, expanding Glasma, revealing gluon and quark distribution behaviors that resemble classical simulations and suggest universal self-similar scaling.

## Contribution

It demonstrates that a kinetic Boltzmann approach captures key features of Glasma evolution, including gluon cascades and self-similar quark distributions, aligning with classical-statistical results.

## Key findings

- Gluon distributions show infrared enhancement similar to Bose-Einstein condensation.
- Quark distributions exhibit self-similar scaling behavior.
- Results challenge traditional thermalization scenarios.

## Abstract

We report on a numerical study of the Boltzmann equation including $2\leftrightarrow 2$ scatterings of gluons and quarks in an overoccupied Glasma undergoing longitudinal expansion. We find that when a cascade of gluon number to the infrared occurs, corresponding to an infrared enhancement analogous to a transient Bose-Einstein condensate, gluon distributions qualitatively reproduce the results of classical-statistical simulations for the expanding Glasma. These include key features of the distributions that are not anticipated in the "bottom-up" thermalization scenario. We also find that quark distributions, like those of gluons, satisfy self-similar scaling distributions in the overoccupied Glasma. We discuss the implications of these results for a deeper understanding of the self-similarity and universality of parton distributions in the Glasma.