Properties of charmonium in lattice QCD with 2 + 1 flavors of improved staggered sea quarks

Abstract We use the dynamical gluon configurations provided by the MILC collaboration in a study of the charmonium spectrum and ψ leptonic width. We examine sea quark effects on mass splitting and on the leptonic decay matrix element for light masses as low as ms/5, while keeping the strange quark mass fixed and the lattice spacing nearly constant.