QCD spectrum with three quark flavors - art. no. 054506

We present results from a lattice hadron spectrum calculation using three f lavors of dynamical quarks - two light and one strange-and quenched simulat ions for comparison. These simulations were done using a one-loop Symanzik improved gauge action and an improved Kogut-Susskind quark action. The latt ice spacings, and hence also the physical volumes, were tuned to be the sam e in all the runs to better expose differences due to flavor number. Lattic e spacings were tuned using the static quark potential, so as a by-product we obtain updated results for the effect of sea quarks on the static quark potential. We find indications that the full QCD meson spectrum is in bette r agreement with experiment than the quenched spectrum. For the 0(+ +) (a(0 )) meson we see a coupling to two pseudoscalar mesons, or a meson decay on the lattice.