Curvature of the pseudocritical line in QCD: Taylor expansion matches analytic continuation

Abstract

We determine the curvature of the pseudocritical line of ${N}_{f}=2+1$ QCD with physical quark masses via Taylor expansion in the quark chemical potentials. We adopt a discretization based on stout improved staggered fermions and the tree level Symanzik gauge action; the location of the pseudocritical temperature is based on chiral symmetry restoration. Simulations are performed on lattices with different temporal extent (${N}_{t}=6$, 8, 10), leading to a continuum extrapolated curvature $\ensuremath{\kappa}=0.0145(25)$, which is in very good agreement with the continuum extrapolation obtained via analytic continuation and the same discretization, $\ensuremath{\kappa}=0.0135(20)$. This result eliminates the possible tension emerging when comparing analytic continuation with earlier results obtained via Taylor expansion.