Quark mass effects on the topological susceptibility in QCD

Abstract

We investigate topology in lattice simulations of QCD with two flavors of dynamical Wilson fermions. At various sea quark masses we find reasonable agreement between results for the topological charge from fermionic and gluonic definitions, the latter with cooling. We study correlations of the topological charge with light hadronic observables and find effects in the flavor singlet pseudoscalar channel. The quark mass dependence of the topological susceptibility $\ensuremath{\chi}$ is consistent with the leading order small ${m}_{\ensuremath{\pi}}$ expectation, $\ensuremath{\chi}{=f}_{\ensuremath{\pi}}^{2}{m}_{\ensuremath{\pi}}^{2}/4.$