Speaker
Description
Quenched QCD at zero baryonic chemical potential undergoes a
deconfinement phase transition at a critical temperature $T_c$, which is
related to the spontaneous breaking of the global center symmetry.
Including heavy but dynamical quarks breaks the center symmetry
explicitly and weakens the first order phase transition. For
decreasing quark masses the first order phase transition turns
into a smooth crossover at a critical $Z_2$ point. The critical quark
mass corresponding to this point has been examined with $N_f=2$ Wilson
fermions for several $N_\tau$ in a recent study within our group. For
comparison, we also localize the critical $Z_2$ point with $N_f=2$
staggered fermions on $N_\tau=8$ lattices. For this purpose we perform
Monte Carlo simulations for several quark mass values and various aspect
ratios in order to extrapolate to the thermodynamic limit. The critical
mass is obtained by fitting to a finite size scaling formula of the
kurtosis of the Polyakov loop. Our results indicate large cutoff
effects, requiring simulations on lattices with $N_\tau>8$.
