As a test of the chiral properties of the improved Asqtad (staggered fermion) action, we have been measuring the topological susceptibility as a function of quark masses for 2 + 1 dynamical flavors. We report preliminary results, which show reasonable agreement with leading order chiral perturbation theory for lattice spacing less than 0.1 fm. The total topological charge, however, shows strong persistence over Monte Carlo time.
@article{arxiv.hep-lat/0209050,
title = {Topological susceptibility with the improved Asqtad action},
author = {MILC Collaboration and C. Bernard and T. Burch and T. A. DeGrand and C. E. DeTar and Steven Gottlieb and E. Gregory and A. Hasenfratz and U. M. Heller and J. Hetrick and J. Osborn and R. L. Sugar and D. Toussaint},
journal= {arXiv preprint arXiv:hep-lat/0209050},
year = {2009}
}