Scaling of Pseudo-Critical Couplings in Two-Flavour QCD

Abstract

We study the scaling behaviour of the pseudo-critical couplings for the chiral phase transition in two-flavour QCD. We show that all existing results from lattice simulations on lattices with temporal extent $N_τ= 4$, 6 and 8 can be mapped onto a universal scaling curve. The relevant combination of critical exponents, $βδ$, is consistent with the scaling behaviour expected for a second order phase transition with $O(4)$ exponents. At present, scaling according to the $O(2)$ symmetry group can, however, not be ruled out.