Overlap between Lattice QCD and HRG with in-medium effects and parity doubling

TL;DR

This study explores how in-medium effects and parity doubling influence baryon fluctuations in hot hadronic matter, comparing lattice QCD results with a hadron resonance gas model incorporating temperature-dependent masses.

Contribution

It introduces a framework combining lattice QCD data and chiral models to analyze in-medium effects on baryon fluctuations, highlighting the need for more comprehensive treatments beyond mass shifts.

Findings

Hyperon mass shifts can reproduce some correlation ratios.

Mass shifts tend to overshoot fluctuations and correlations.

A more complete in-medium effect model is necessary.

Abstract

We investigate the fluctuations and correlations involving baryon number in hot hadronic matter with modified masses of negative-parity baryons, in the context of the hadron resonance gas. Temperature-dependent masses are adopted from the recent lattice QCD results and from a chiral effective model which implements the parity doubling structure with respect to the chiral symmetry. Confronting the baryon number susceptibility, baryon-charge correlation, and baryon-strangeness correlation and their ratios with the lattice QCD data, we show that the strong downward mass shift in hyperons can accidentally reproduce some correlation ratios, however it also tends to overshoot the individual fluctuations and correlations. This indicates, that in order to correctly account for the influence of the chiral symmetry restoration on the fluctuation observables, a consistent framework of in-medium effects beyond hadron mass shifts is required.