Equation of State of hot and dense QCD: Resummed perturbation theory confronts lattice data

TL;DR

This paper compares resummed perturbation theory predictions for the thermodynamics of hot, dense QCD with lattice data, demonstrating convergence and improved accuracy through various resummation techniques.

Contribution

It provides a detailed comparison of HTLpt and dimensional reduction methods against lattice results, including an exact one-loop calculation and a resummation of four-loop expressions.

Findings

Resummed perturbation theory shows good convergence.

Theoretical predictions align well with lattice data.

Resummation improves the accuracy of QCD thermodynamics calculations.

Abstract

We perform a detailed analysis of the predictions of resummed perturbation theory for the pressure and the second-, fourth-, and sixth-order diagonal quark number susceptibilities in a hot and dense quark-gluon plasma. First, we present an exact one-loop calculation of the equation of state within hard-thermal-loop perturbation theory (HTLpt) and compare it to a previous one-loop HTLpt calculation that employed an expansion in the ratios of thermal masses and the temperature. We find that this expansion converges reasonably fast. We then perform a resummation of the existing four-loop weak coupling expression for the pressure, motivated by dimensional reduction. Finally, we compare the exact one-loop HTLpt and resummed dimensional reduction results with state-of-the-art lattice calculations and a recent mass-expanded three-loop HTLpt calculation.