Perturbative study of the QCD phase diagram for heavy quarks at nonzero chemical potential: Two-loop corrections

J Maelger,J Serreau,U Reinosa

doi:10.1103/physrevd.97.074027

Abstract

We extend a previous investigation of the QCD phase diagram with heavy quarks in the context of background field methods by including the two-loop corrections to the background field effective potential. The nonperturbative dynamics in the pure-gauge sector is modeled by a phenomenological gluon mass term in the Landau-DeWitt gauge-fixed action, which results in an improved perturbative expansion. We investigate the phase diagram at nonzero temperature and (real or imaginary) chemical potential. Two-loop corrections yield an improved agreement with lattice data as compared to the leading-order results. We also compare with the results of nonperturbative approaches. We further study the equation of state as well as the thermodynamic stability of the system at two-loop order. Finally, we show, using simple thermodynamic arguments, that the behavior of the Polyakov loops as functions of the chemical potential complies with their interpretation in terms of quark and anti-quark free energies.

Highlights

The phase diagram of QCD is the subject of intense theoretical and experimental investigations [1,2,3,4]
A large panel of theoretical methods has been developed to explore the phase diagram of QCD matter in thermodynamic equilibrium at finite nonzero temperature T, baryon chemical potential μ, magnetic field B, etc., ranging from lattice Monte Carlo simulations [9,10,11,12] to various continuum approaches either in QCD [13,14,15,16,17,18,19] or using low-energy effective models [20,21,22]
We investigate various thermodynamical observables, such as the pressure, the energy density, or the entropy, and we study the thermodynamical stability at the present order of approximation

Summary

Introduction

The phase diagram of QCD is the subject of intense theoretical and experimental investigations [1,2,3,4]. A large panel of theoretical methods has been developed to explore the phase diagram of QCD matter in thermodynamic equilibrium at finite nonzero temperature T, baryon chemical potential μ, magnetic field B, etc., ranging from lattice Monte Carlo simulations [9,10,11,12] to various continuum approaches either in QCD [13,14,15,16,17,18,19] or using low-energy effective models [20,21,22] The former, when available, is capable of tackling the exact nonperturbative dynamics of the theory and are essentially limited by statistical errors. The latter, instead, directly access averaged quantities, such as correlation

Objectives

Results

Conclusion