The equation of state of quark-gluon matter from lattice QCD with two flavors of twisted-mass Wilson fermions

TL;DR

This paper presents lattice QCD calculations of the thermodynamic equation of state for quark-gluon matter with two flavors of twisted-mass Wilson fermions, emphasizing the importance of controlling lattice cutoff effects and comparing results with models and other groups.

Contribution

First lattice QCD study of the equation of state with twisted-mass Wilson fermions for two degenerate flavors, analyzing cutoff effects and comparing with other Nf configurations.

Findings

Trace anomaly results depend on lattice cutoff control.

Results agree with hadron resonance gas at low T.

Comparison with Nf=0 and Nf=2+1 results shows consistency.

Abstract

We report on lattice QCD results for the thermodynamic equation of state of quark-gluon matter obtained with Nf=2 degenerate quark flavors. For the fermion field discretization we are using the Wilson-twisted mass prescription. Simulations have been carried out at three values of the bare quark masses corresponding to pion masses of 360, 430 and 640 MeV. We highlight the importance of a good control of the lattice cutoff dependence of the trace anomaly which we have studied at several values of the inverse temperature 1/T = a Nt with a time-like lattice extent up to Nt=12. We contrast our results with those of other groups obtained for Nf=0 and Nf=2+1. At low temperature we also confront them with hadron resonance gas model predictions for the trace anomaly.