Equation of state of QCD matter within the Hagedorn bag-like model

TL;DR

This paper presents a Hagedorn bag-like model that accurately describes the QCD equation of state at finite temperature and density, capturing the crossover transition between hadronic and quark-gluon matter.

Contribution

The model incorporates finite hadron sizes and an exponential mass spectrum, providing a thermodynamically consistent description aligned with lattice QCD data.

Findings

Quantitative agreement with lattice thermodynamic functions

Reproduction of susceptibilities and Fourier coefficients

Observation of a crossover transition at finite baryon density

Abstract

The QCD equation of state at finite temperature and densities of conserved charges is considered in the framework of a Hagedorn bag-like model, incorporating both the finite sizes of hadrons as well as their exponential mass spectrum. Augmented with non-zero masses of quarks and gluons in the bag spectrum, the model yields a fair quantitative description of lattice data on thermodynamic functions, the conserved charges susceptibilities, and Fourier coefficients of net-baryon density. Both at zero and finite baryon densities a broad crossover transition between hadronic and quark-gluon matter is observed. The model thus provides a thermodynamically consistent construction of a crossover equation of state for finite baryon number, electric charge and strangeness chemical potentials, which can be used in fluid dynamical simulations of heavy-ion collisions.