Axial U(1) symmetry at low and high temperatures in lattice QCD with chiral fermions

Aoki, Shinya*; Aoki, Yasumichi*; Fukaya, Hidenori*; Hashimoto, Shoji*; Kanamori, Issaku*; Kaneko, Takashi*; Nakamura, Yoshifumi*; Rohrhofer, C.*; Suzuki, Kei   ; Ward, D.*

Quantum chromodynamics (QCD) is the fundamental theory describing the dynamics of quarks and gluons. The axial U(1) symmetry in QCD is broken at low temperatures by the effect of quantum anomaly, and it is important for understanding the phase structure of QCD to investigate what happens to this symmetry in the high-temperature regime of QCD. In this study, we simulate a high-temperature regime of 2+1 flavor QCD using dynamical chiral fermions such as the domain-wall fermions and the overlap fermions (obtained by the reweighting method). Here, for up- and down-quark masses, we investigate masses heavier than the physical point, near the physical point, and lighter than the physical point. For temperatures, we investigate the near-pseudo-critical temperature and slightly lower and higher temperature regions. For physical quantities, we report results and discussion on the behavior of the Dirac spectrum, axial U(1) susceptibility, topological susceptibility, and hadronic correlation functions.