The U(1)A anomaly in high temperature QCD with chiral fermions on the lattice

TL;DR

This study investigates the $U_A(1)$ symmetry breaking in high-temperature QCD with chiral fermions on the lattice, focusing on the eigenvalue spectrum near the chiral crossover temperature to understand its impact on the phase transition.

Contribution

The paper provides new lattice QCD results using Mobius domain wall fermions and the overlap operator to analyze the $U_A(1)$ anomaly at finite temperature, comparing different fermion formulations.

Findings

Eigenvalue spectrum sensitivity to sea-light quark mass.

Comparison shows consistency between Mobius domain wall and domain wall fermions.

Results shed light on the role of $U_A(1)$ breaking near $T_c$.

Abstract

The magnitude of the $U_A(1)$ symmetry breaking is expected to affect the nature of $N_f=2$ QCD chiral phase transition. The explicit breaking of chiral symmetry due to realistic light quark mass is small, so it is important to use chiral fermions on the lattice to understand the effect of $U_A(1)$ near the chiral crossover temperature, $T_c$. We report our latest results for the eigenvalue spectrum of 2+1 flavour QCD with dynamical Mobius domain wall fermions at finite temperature probed using the overlap operator on $32^3\times 8$ lattice. We check how sensitive the low-lying eigenvalues are to the sea-light quark mass. We also present a comparison with the earlier independent results with domain wall fermions.