PUB - Publikationen an der Universität Bielefeld

In quenched QCD the Polyakov loop is an order parameter of the deconfinement transition, but with decreasing quark mass, the peak in the Polyakov loop susceptibility becomes less pronounced, and it loses its interpretation as an indicator for deconfinement. For this Nf=2+1 HISQ study, we fix the strange quark mass ms at its physical value and investigate the dependence of the Polyakov loop on the light quark mass ml in the range ms/ml=27−160, following ml toward the chiral limit. In particular we will look how the inflection point and susceptibility behave as we decrease ml, to see whether one finds any indication of a crossover, and therefore whether the Polyakov loop is sensitive to the chiral phase transition. Preliminary results show no signal of a crossover from the real part of the Polyakov loop in the vicinity of the chiral crossover. Closely related is an investigation of Polyakov loop correlations and the Debye mass in this limit. Preliminary results suggest little or no dependence on ml.