More on the QCD phase diagram at finite temperatures

Abstract

In order to broaden the existing knowledge about the phase diagram of QCD, we use a Langevin algorithm to study finite-temperature QCD on an 8³× 4 lattice with variable flavor number, quark mass, and gauge coupling. We concentrate on the search for first-order transitions for small flavor number and light-quark masses. We find general agreement with the predictions of effective models of the finite-temperature deconfinement and chiral-symmetry-restoration phase-transition mechanisms. In particular, we find that the deconfinement transition extends to lower quark masses as n_f, the number of quark flavors, decreases. Nonperturbative fermionic effects are found to be significant for very light quarks even for n_f=0.1AE.