Static quark free energies at finite temperature with two flavors of improved Wilson quarks

TL;DR

This study investigates the free energies of static quark pairs at finite temperature in two-flavor QCD using lattice simulations with improved Wilson quarks, analyzing screening effects and comparing with perturbative and previous results.

Contribution

It provides new lattice QCD results for static quark free energies, Debye screening mass, and effective coupling with improved Wilson quarks at finite temperature.

Findings

Free energies follow screened Coulomb form with Casimir scaling.

Debye mass agrees with perturbative and phenomenological models.

Comparison shows consistency with previous staggered quark results.

Abstract

Polyakov loop correlations at finite temperature in two-flavor QCD are studied in lattice simulations with the RG-improved gluon action and the clover-improved Wilson quark action. From the simulations on a $16^3 \times 4$ lattice, we extract the free energies, the effective running coupling $g_{\rm eff}(T)$ and the Debye screening mass $m_D(T)$ for various color channels of heavy quark--quark and quark--anti-quark pairs above the critical temperature. The free energies are well approximated by the screened Coulomb form with the appropriate Casimir factors. The magnitude and the temperature dependence of the Debye mass are compared to those of the next-to-leading order thermal perturbation theory and to a phenomenological formula given in terms of $g_{\rm eff}(T)$. Also we made a comparison between our results with the Wilson quark and those with the staggered quark previously reported.