Thermodynamically consistent treatment of repulsive corrections in HRG

TL;DR

This paper introduces a thermodynamically consistent method for incorporating repulsive interactions in the hadron resonance gas model, accurately matching lattice QCD results with minimal parameters.

Contribution

It reformulates density-dependent chemical potential shifts using an auxiliary classical representation to ensure thermodynamic consistency in the HRG model.

Findings

Reproduces lattice QCD susceptibilities with two parameters.

Ensures thermodynamic consistency in excluded-volume HRG models.

Uses a liquid-drop inspired parametrization for hadron radii.

Abstract

We reformulate the treatment of density-dependent chemical potential shifts appearing in excluded-volume implementations of the hadron resonance gas model. An auxiliary classical representation is constructed in which a common energy shift is determined by preserving the scalar number density, ensuring thermodynamic consistency. Hadron radii are parametrized through a liquid-drop inspired mass-radius relation with two parameters: the pion radius and a scaling exponent. The resulting framework reproduces lattice QCD results for lower-order conserved-charge susceptibilities at zero chemical potentials with only two adjustable parameters.