Susceptibilities, the specific heat, and a cumulant in two-flavor QCD

We study the quark mass dependence of various response functions, which contribute to chiral susceptibilities and the specific heat in the staggered fermion formulation of two-flavor QCD. This yields information about the critical exponents {α}, {β}, and {δ}. In the case of the chiral susceptibility, obtained as a derivative of the chiral order parameter with respect to the quark mass, we calculate all contributions. This allows us to construct a cumulant of the order parameter, which is a scaling function and yields a direct determination of the critical exponent {δ}. All our results are consistent with a second order phase transition.