The flavor dependence of the QCD finite temperature phase transition

We present finite temperature full QCD simulations on 163 × Nt obtained with the 256-node Columbia Parallel processor during the last year. We see a first order transition with four flavors at Nt = 4 for mqa = 0.01, 0.025, 0.0375, and 0.05, and at Nt = 6 for mqa = 0.01 but not for mqa = 0.025, suggesting that the transition weakens as we move closer to the continuum limit. With two flavors at Nt = 4 we do not see a transition for mqa = 0.01 and 0.025. With three flavors at Nt = 4 we see a first order transition for mqa = 0.025; fixing mu, da = 0.025 and increasing the strange quark mass to msa = 0.1 we find no evidence of a transition and that mK/mp = 0.46(1), raising the possibility that in nature QCD may not undergo a finite temperature phase transition.