CRITICAL MASS IN NONZERO TEMPERATURE QCD WITH STAGGERED FERMIONS

The behaviour of the chiral condensate in QCD is investigated by means of a study of the distribution of the zeros of the partition function in the complex quark-mass plane. Simulations are performed at fixed temperature on three different spatial volumes at beta = 5.04 and at beta = 4.9 and beta = 5.2 on a 4(4) lattice. Evidence is found for a chirally related transition at non-zero quark mass in the intermediate coupling region for beta < 5.2 but superimposed upon a smooth behaviour for the condensate. The critical mass at which this transition is found in only weakly dependent on the spatial volume and decreases with decreasing temperature.