# QCD matter with a crossover and a first-order phase transition

## TL;DR

This paper introduces a phenomenological model of the QCD phase diagram that smoothly transitions between crossover, critical point, and first-order phase transition regions, aiding the study of heavy-ion collision phenomena.

## Contribution

It provides a flexible parametrization of the QCD phase diagram with a switching function controlling the transition types, including a critical point, for phenomenological applications.

## Key findings

- The EOS captures a crossover at high T and low μ.
- It models a critical point along the phase transition line.
- It describes a first-order transition at low T and high μ.

## Abstract

We present a phenomenological parametrization of the phase diagram of QCD as a function of temperature $T$ and baryochemical potential $\mu$. The parametrization is constructed by introducing a switching function which controls the nature of the transition between the Hadron-Resonance Gas (HRG) and Quark-Gluon Plasma (QGP) phases of nuclear matter, such that the equation of state (EOS) possesses a rapid crossover at large $T$ and small $\mu$, a critical point placed anywhere along the phase transition line, and a first-order transition at small $T$ and large $\mu$. This EOS offers a convenient phenomenological tool for assessing the possible effects of the conjectured QCD critical point on heavy-ion observables.