Topological susceptibility on dynamical staggered fermion configurations

Topological susceptibility is one of the few physical quantities that directly measures the properties of the QCD vacuum. Chiral perturbation theory predicts that in the small quark mass limit the topological susceptibility depends quadratically on the pion mass, approaching zero in the chiral limit. Lattice calculations have difficulty reproducing this behavior. In this paper we study the topological susceptibility on dynamical staggered fermion configurations. Our results indicate that the lattice spacing has to be small, around $a\approx 0.1\hspace{0.5em}\mathrm{fm},$ for thin link staggered fermion actions to show the expected chiral behavior. Our preliminary result indicates that fat link fermions, on the other hand, reproduce the theoretical expectations even on lattices with $a\approx 0.17\hspace{0.5em}\mathrm{fm}.$ We argue that this is due to the improved flavor symmetry of fat link fermionic actions.