The QCD Deconfinement Critical Point for $N_\text{f}=2$ Flavors of Staggered Fermions

TL;DR

This study investigates the critical point of the deconfinement phase transition in two-flavor QCD using staggered fermions, highlighting significant discretization effects and the need for larger lattice simulations.

Contribution

It provides a comparison of the critical quark mass for the deconfinement transition using staggered fermions at N_tau=8 with previous Wilson fermion results, emphasizing discretization effects.

Findings

Large discretization effects observed at N_tau=8.

Critical quark mass determined via finite size scaling of Polyakov loop kurtosis.

Simulations suggest the need for N_tau > 8 for more accurate results.

Abstract

Quenched QCD at zero baryonic chemical potential undergoes a first-order deconfinement phase transition at a critical temperature $T_c$, which is related to the spontaneous breaking of the global center symmetry. Including heavy, 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 $Z_2$-critical point. The critical quark mass corresponding to this point has been examined with $N_\text{f} = 2$ Wilson fermions for several $N_\tau$ in a recent study within our group. For comparison, we also locate the critical point with $N_\text{f} = 2$ 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 discretization effects, requiring simulations on lattices with $N_\tau > 8$.