The curvature of the QCD critical line from analytic continuation

We determine the curvature of the pseudo-critical line of strong interactions, coping with the sign problem by the method of analytic continuation from an imaginary chemical potential.We consider N f = 2+ 1 stout improved staggered fermions and the tree level Symanzik gauge action, studying Nt = 6 and Nt = 8 lattices for physical quark masses. The pseudocritical temperatures are evaluated by looking at the T dependence of the renormalized chiral condensate and of the renormalized chiral susceptibility. The determinations of the curvature obtained from the two quantities are in good agreement. Moreover, we investigate the effect of including a non-zero strange quark chemical potential and compare our results to previous determinations in the literature.