Critical scaling at the QCDNf=2chiral phase transition

Abstract

We investigate the critical scaling of the quark propagator of ${N}_{f}=2$ QCD close to the chiral phase transition at finite temperature. We argue that it is mandatory to take into account the backreaction effects of pions and the sigma onto the quark to observe critical behavior beyond mean field. On the condition of self-consistency of the quark Dyson-Schwinger equation we extract the scaling behavior for the quark propagator analytically. Crucial in this respect is the correct pion dispersion relation when the critical temperature is approached from below. Our results are consistent with the known relations for the quark condensate and the pion decay constant from universality. We verify the analytical findings also numerically assuming the critical dispersion relation for the Goldstone bosons.