The Chiral Critical Point in 3-Flavour QCD

TL;DR

This paper investigates the nature of the chiral critical point in 3-flavour QCD at finite temperature, identifying its universality class and the conditions under which the phase transition is first order.

Contribution

It precisely locates the second order endpoint of the first order transition line and confirms its universality class as 3d Ising, providing detailed analysis and estimates for transition conditions.

Findings

Chiral critical point belongs to 3d Ising universality class

Transition is first order for pseudo-scalar meson masses below ~200 MeV

Binder cumulants confirm universal properties of the critical point

Abstract

We determine the second order endpoint of the line of first order phase transitions, which occur in the light quark mass regime of 3-flavour QCD at finite temperature, and analyze universal properties of this chiral critical point. A detailed analysis of Binder cumulants and the joint probability distributions of energy like and ordering-field like observables confirms that the chiral critical point belongs to the universality class of the 3d Ising model. From a calculation with improved gauge and staggered fermion actions we estimate that the transition is first order for pseudo-scalar meson masses less than about 200 MeV.