Polyakov loop fluctuations and deconfinement in the limit of heavy   quarks
  We explore the influence of heavy quarks on the deconfinement phase transition in an effective model for gluons interacting with dynamical quarks in color SU(3). With decreasing quark mass, the strength of the explicit breaking of the Z(3) symmetry grows and the first-order transition ends in a critical endpoint. The nature of the critical endpoint is examined by studying the longitudinal and transverse fluctuations of the Polyakov loop, quantified by the corresponding susceptibilities. The longitudinal susceptibility is enhanced in the critical region, while the transverse susceptibility shows a monotonic behavior across the transition point. We investigate the dependence of the critical endpoint on the number of quark flavors at vanishing and finite quark density. Finally we confront the model results with lattice calculations and discuss a possible link between the hopping parameter and the quark mass. 
Pok Man Lo, Bengt Friman, and Krzysztof Redlich
hep-ph