Embedding a critical point in a hadron to quark-gluon crossover equation of state

TL;DR

This paper presents a method to incorporate a critical point into a smooth hadron-quark-gluon crossover equation of state, aligning with expected universality class critical exponents, aiding heavy ion collision modeling.

Contribution

It introduces a way to embed a critical point into a smooth equation of state consistent with 3D Ising universality class, useful for heavy ion collision analysis.

Findings

The equation of state exhibits correct critical exponents.

Parameters can be inferred from hydrodynamic modeling.

Supports experimental searches for the QCD critical point.

Abstract

Lattice QCD simulations have shown unequivocally that the transition from hadrons to quarks and gluons is a crossover when the baryon chemical potential is zero or small. Many model calculations predict the existence of a critical point at a value of the chemical potential where current lattice simulations are unreliable. We show how to embed a critical point in a smooth background equation of state so as to yield the critical exponents and critical amplitude ratios expected of a transition in the same universality class as the liquid-gas phase transition and the 3D Ising model. The resulting equation of state has parameters which may be inferred by hydrodynamic modeling of heavy ion collisions in the Beam Energy Scan II at the Relativistic Heavy Ion Collider or in experiments at other accelerators.