Diffusion or bounce back in relativistic heavy-ion collisions?

TL;DR

This paper compares a relativistic diffusion model and a bounce-back model to describe the evolution of charged hadron distributions in heavy-ion collisions, finding the diffusion model aligns better with experimental data, indicating thermalization.

Contribution

It introduces a nonequilibrium-statistical diffusion model with three sources for analyzing pseudorapidity distributions in heavy-ion collisions, highlighting the importance of statistical equilibration.

Findings

Diffusion model provides more accurate data description.

System appears to be approaching thermal equilibrium.

Bounce-back model does not fit data as well.

Abstract

The time evolution of pseudorapidity distributions of produced charged hadrons in d+Au collisions at sqrt(s_NN) = 200 GeV is investigated. Results of a nonequilibrium-statistical Relativistic Diffusion Model with three sources are compared with a macroscopic "bounce back" model that does not allow for statistical equilibration at large times, but instead leads to motion reversal. When compared to the data, the results of the diffusion approach are more precise, thus emphasizing that the system is observed to be on its way to thermal equilibrium.