FINITE-SIZE AND QUARK MASS EFFECTS ON THE QCD SPECTRUM WITH 2 FLAVORS

We have carried out spectrum calculations with two flavors of dynamica l Kogut-Susskind quarks on four lattice sizes from 8(3) X 24 to 16(3) X 24 at couplings that correspond to chiral symmetry restoration for a lattice with six time slices. We estimate that the linear spatial siz es of the lattices range from 1.8 to 3.6 fm. We find significant finit e-size effects for all particles between the smallest and largest volu me with the larger quark mass that we study, am(q) = 0.025, where a is the lattice spacing. The nucelon experiences the largest effect of ab out 6%. We also study a lighter quark mass, am(q) = 0.0125, on the two largest lattices. Effects of the dynamical and valence quark masses o n the hadron spectrum are studied both directly, by comparing the two simulations, and by extracting mass derivatives from the correlation f unctions. We do not find much improvement in the nucleon to rho mass r atio as we decrease the quark mass at this lattice spacing. Finally, w e report on an unsuccessful attempt to see effects of the rho-->2pi de cay on the rho mass, and on studies of Wilson and Kogut-Susskind hadro n masses with large valence quark masses.