The Chiral Phase Transition in three-flavor QCD from Lattice QCD

TL;DR

This study investigates the nature of the chiral phase transition in three-flavor QCD using lattice simulations with improved staggered quarks, finding evidence for a second order transition and estimating the transition temperature.

Contribution

It provides the first detailed lattice analysis of the chiral phase transition in three-flavor QCD at physical quark masses with improved actions.

Findings

Evidence for a second order chiral phase transition at zero quark mass.

Estimated transition temperature at finite lattice spacing is around 98 MeV.

Projected continuum limit transition temperature is below 90 MeV.

Abstract

We analyze the pseudo-critical behavior of three-flavor QCD using highly improved staggered quarks (HISQ) on lattices with temporal extent $N_\tau =8$ and for quark masses corresponding to a pseudoscalar Goldstone mass in the range $80 ~ {\rm MeV} ~ \lesssim ~ m_\pi ~ \lesssim ~ 140 ~ {\rm MeV}$. Our findings are consistent with the occurrence of a second order chiral phase transition at vanishing values of the quark masses. The chiral phase transition temperature at this finite value of the lattice spacing is determined to be $T_c = 98_{-6}^{+3}~{\rm MeV}$. A comparison with a corresponding analysis performed in (2+1)-flavor QCD suggests that the continuum limit extrapolated chiral phase transition temperature in 3-flavor QCD will turn out to be below $90 ~ {\rm MeV}$.