Finite-size and Quark Mass Eeects on the Qcd Spectrum with Two Avors Ips, Rz F 3, Eth-zentrum Ch-8092 Zurich, Switzerland

We have carried out spectrum calculations with two avors of dynamical KogutSusskind quarks on four lattice sizes from 83 24 to 163 24 at couplings that correspond to chiral symmetry restoration for a lattice with 6 time slices. We estimate that the linear spatial sizes of the lattices range from 1.8 to 3.6 fm. We nd signi cant nite size e ects for all particles between the smallest and largest volume with the larger quark mass that we study, amq = 0:025, where a is the lattice spacing. The nucleon experiences the largest e ect of about 6 percent. We also study a lighter quark mass, amq = 0:0125, on the two largest lattices. E ects of the dynamical and valence quark masses on the hadron spectrum are studied both directly, by comparing the two simulations, and by extracting mass derivatives from the correlation functions. We do not nd much improvement in the nucleon to rho mass ratio as we decrease the quark mass at this lattice spacing. Finally, we report on an unsuccessful attempt to see e ects of the ! 2 decay on the mass, and on studies of Wilson and Kogut-Susskind hadron masses with large valence quark masses. 2