Lattice QCD-based equations of state at vanishing net-baryon density

TL;DR

This paper develops realistic equations of state for QCD matter at zero net-baryon density by combining lattice QCD results with a hadron resonance gas model, including partial chemical equilibrium, to improve hydrodynamic simulations of heavy-ion collisions.

Contribution

It introduces a new set of equations of state that incorporate recent lattice QCD data and partial chemical equilibrium, enhancing the realism of modeling QCD matter in heavy-ion collisions.

Findings

Equations of state are consistent with lattice QCD results at high temperatures.

Inclusion of partial chemical equilibrium allows better experimental data matching.

Parametrizations provided facilitate hydrodynamic modeling applications.

Abstract

We present realistic equations of state for QCD matter at vanishing net-baryon density which embed recent lattice QCD results at high temperatures combined with a hadron resonance gas model in the low-temperature, confined phase. In the latter, we allow an implementation of partial chemical equilibrium, in which particle ratios are fixed at the chemical freeze-out, so that a description closer to the experimental situation is possible. Given the present uncertainty in the determination of the chemical freeze-out temperature from first-principle lattice QCD calculations, we consider different values within the expected range. The corresponding equations of state can be applied in the hydrodynamic modeling of relativistic heavy-ion collisions at the LHC and at the highest RHIC beam energies. Suitable parametrizations of our results as functions of the energy density are also provided.