Fluctuations and Higher Moments of Conserved Charges from the Lattice

TL;DR

This paper reports lattice QCD calculations of quark number susceptibilities using the HISQ action, revealing a crossover from hadronic to quark matter with significant interactions, aligning with Hadron Resonance Gas models below the transition.

Contribution

First lattice QCD study using HISQ action at near-physical pion mass to compute quark number susceptibilities and analyze the crossover transition.

Findings

Broad crossover observed from hadronic to quark regimes

Results agree with Hadron Resonance Gas models below transition

Interactions remain significant at high temperatures

Abstract

We present results for the lowest-order non-vanishing quark number susceptibilities. These were calculated using an improved action viz. the HISQ action, which controls taste violations that are responsible for distorting the light meson spectrum. Our calculations, with a pion mass of 160 MeV, are also much closer to the physical limit than previous studies. We find a broad crossover from the hadronic to the quark regimes, although interactions remain significant even at the highest temperatures studied. Our results are also in good agreement with Hadron Resonance Gas models below the crossover temperature.