Higher moments of charge fluctuations in QCD at high temperature

TL;DR

This paper presents lattice QCD results on charge fluctuations and correlations at high temperature, showing rapid changes at the transition temperature and convergence to ideal quark gas behavior above 1.5 times that temperature.

Contribution

It provides the first detailed lattice QCD analysis of higher moments of charge fluctuations at finite temperature relevant for heavy-ion collisions.

Findings

Fluctuations change rapidly at the transition temperature.

Fluctuations approach ideal quark gas limits above 1.5T_c.

Hadron resonance gas model describes low-temperature features.

Abstract

We present lattice results for baryon number, strangeness and electric charge fluctuations as well as their correlations at finite temperature and vanishing chemical potentials, i.e. under conditions relevant for RHIC and LHC. We find that the fluctuations change rapidly at the transition temperature $T_c$ and approach the ideal quark gas limit already at approximately $1.5T_c$. This indicates that quarks are the relevant degrees of freedom that carry the quantum numbers of conserved charges at $T\geq 1.5T_c$. At low temperature, qualitative features of the lattice results are well described by a hadron resonance gas model.