NATURE OF THE FINITE-TEMPERATURE TRANSITION IN QCD WITH STRANGE QUARK

The finite temperature transition in QCD is studied using Wilson quarks for the cases of N-F = 2, 3 and 2+1. For N-F = 2 the transition is smooth in the chiral limit on both N-t = 4 and 6 lattices. For N-F = 3, clear two state signals are observed for beta less than or equal to 4.7 on 8(2) x 10 x 4 and 12(3) x 4 lattices, which implies the transition is first order for m(q) less than or similar to 140 MeV. For N-F = 2 + 1 we study two cases of m(s) similar or equal to 150 and 400 MeV with m(s) = m(d) similar or equal to 0. In contrast to a previous result with staggered quarks, two state signals are clearly observed for both cases, suggesting a first order QCD phase transition in the real world.