The QCD phase diagram at nonzero quark density

We determine the phase diagram of QCD on the μ − T plane for small to moderate chemical potentials. Two transition lines are defined with two quantities, the chiral condensate and the strange quark number susceptibility. The calculations are carried out on Nt =6, 8 and 10 lattices generated with a Symanzik improved gauge and stout-link improved 2+ 1 flavor staggered fermion action using physical quark masses. After carrying out the continuum extrapolation we find that both quantities result in a similar curvature of the transition line. Furthermore, our results indicate that in leading order the width of the transition region remains essentially the same as the chemical potential is increased.