Isotropization and hydrodynamization in weakly coupled heavy-ion collisions

TL;DR

This study numerically investigates the early evolution of heavy-ion collisions using effective kinetic theory, demonstrating that the system rapidly approaches hydrodynamic behavior consistent with classical simulations, especially under CGC-motivated initial conditions.

Contribution

It provides the first detailed numerical analysis of isotropization and hydrodynamization in weakly coupled QCD with longitudinal expansion, bridging kinetic theory and hydrodynamics.

Findings

Agreement with viscous hydrodynamics and classical Yang-Mills simulations

Hydrodynamic behavior emerges before 1.0 fm/c for specific parameters

Initial conditions based on color-glass-condensate are consistent with early hydrodynamization

Abstract

We numerically solve 2+1D effective kinetic theory of weak coupling QCD under longitudinal expansion relevant for early stages of heavy-ion collisions. We find agreement with viscous hydrodynamics and classical Yang-Mills simulations in the regimes where they are applicable. By choosing initial conditions that are motivated by color-glass-condensate framework we find that for Q=2GeV and $\alpha_s$=0.3 the system is approximately described by viscous hydrodynamics well before $\tau \lesssim 1.0$ fm/c.