Axial U(1) symmetry at high temperature in 2-flavor lattice QCD

We investigate the axial U (1) A symmetry breaking above the critical temperature in two-flavor lattice QCD. The ensembles are generated with dynamical Mobius domain-wall or reweighted overlap fermions. The U (1) A susceptibility is extracted from the low-modes spectrum of the overlap Dirac eigenvalues. We show the quark mass and temperature dependences of U (1) A susceptibility. Our results at T = 220MeV imply that the U (1) A symmetry is restored in the chiral limit. Its coincidence with vanishing topological susceptibility is observed.