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-flavour QCD. This yields information about the critical exponents α, β and δ. In the case of the chiral susceptibility, obtained as derivative of the chiral order parameter with respect to the quark mass, we calculate all contributions. This allows 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.