Topological susceptibility in three-flavor quark-meson model at finite temperature

We study UA(1) symmetry and its relation to chiral symmetry at finite temperature through the application of the functional renormalization group to the SU(3) quark-meson model. Very different from the mass gap and mixing angel between η and η′ mesons, which are defined at the mean-field level and behavior like condensates, the topological susceptibility includes a fluctuation-induced part which becomes dominant at high temperature. As a result, the UA(1) symmetry is still considerably broken in the chiral symmetry restoration phase.