Chiral phase transition of (2 + 1)-flavor QCD on $N_{\tau} = 6$ lattices

TL;DR

This study investigates the chiral phase transition in (2+1)-flavor QCD using HISQ lattice simulations at N_tau=6, exploring temperature and quark mass effects to understand critical behavior near the transition.

Contribution

The paper extends previous lattice QCD studies by analyzing a wider temperature range and multiple light quark masses to better understand the universal scaling of the chiral phase transition.

Findings

Identified the temperature window of the chiral transition up to 170 MeV.

Analyzed the dependence of chiral condensates and susceptibilities on temperature and quark mass.

Discussed the criticality window and its implications for QCD phase structure.

Abstract

We present updated studies on the chiral phase transition in $N_{f}=2+1$ QCD. Simulations have been carried out using Highly Improved Staggered Quarks (HISQ) on lattices with temporal extent $N_{\tau} = 6$ at vanishing baryon chemical potential. We updated our previous study \cite{Ding:2015pmg} by extending the temperature window from (140 MeV, 150 MeV) to (140 MeV, 170 MeV). The strange quark mass was chosen to its physical value $m_{s}^{\mathrm{phy}}$, and five values of two degenerate light quark masses are varied from $m_{s}^{\mathrm{phy}}/80$ to $m_{s}^{\mathrm{phy}}/20$ which correspond to a Goldstone pion mass ranging from 80 MeV to 160 MeV in the continuum limit. The universal scaling behaviour of the QCD chiral phase transition is investigated by studying the temperature and quark mass dependences of chiral condensates and chiral susceptibilities. The window of criticality compared to previous studies is also discussed.