Flavour degrees of freedom and the transition temperature in QCD

We study the finite temperature transition in QCD with four flavours of dynamical quarks. Our simulation is performed on an 8× 163 lattice for quarks of mass ma=0.01. At the coupling βc=5.15, we find long-lived metastable states, as well as an abrupt change in the entropy density, suggesting a first order phase transition. Using presently available results from corresponding calculations of the hadron masses and the chiral condensate, this gives us a transition temperature Tc≅100 MeV, which is a factor two lower than the transition temperature found in quenched QCD