Effective kinetic description of the expanding overoccupied Glasma

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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.