Prescaling and far-from-equilibrium hydrodynamics in the quark-gluon plasma

TL;DR

This paper investigates prescaling in the quark-gluon plasma, showing that gluon and quark distributions rapidly adopt a universal self-similar form, leading to far-from-equilibrium hydrodynamics.

Contribution

It demonstrates the occurrence of prescaling in QCD kinetic theory and links it to far-from-equilibrium hydrodynamics through evolving scaling exponents.

Findings

Gluon and quark distributions quickly adopt a universal scaling form.

Prescaling dynamics are governed by a few slowly evolving scaling exponents.

The results are independent of initial conditions and system parameters.

Abstract

Prescaling is a far-from-equilibrium phenomenon which describes the rapid establishment of a universal scaling form of distributions much before the universal values of their scaling exponents are realized. We consider the example of the spatio-temporal evolution of the quark-gluon plasma explored in heavy-ion collisions at sufficiently high energies. Solving QCD kinetic theory with elastic and inelastic processes, we demonstrate that the gluon and quark distributions very quickly adapt a self-similar scaling form, which is independent of initial condition details and system parameters. The dynamics in the prescaling regime is then fully encoded in a few time-dependent scaling exponents, whose slow evolution gives rise to far-from-equilibrium hydrodynamic behavior.