Cold Quark Matter: Renormalization Group Improvement at next-to-next-to leading order

TL;DR

This paper advances the calculation of QCD pressure at high densities by applying a renormalization group optimized perturbation theory at NNLO, reducing uncertainties and improving convergence over previous methods.

Contribution

It extends NNLO QCD pressure calculations using RGOPT, incorporating strange quark mass effects and demonstrating improved stability and reduced scale dependence.

Findings

Reduced sensitivity to renormalization scale variations.

Enhanced convergence properties of the perturbative series.

Potential for more reliable predictions at high baryonic densities.

Abstract

We extend previous next-to-next-to leading order (NNLO) calculations of the QCD pressure at zero temperature and non-zero baryonic densities using the renormalization group optimized perturbation theory (RGOPT), which entails an all-order RG-invariant resummation. First, we consider the approximation of three massless quark flavors, and then adding the running strange quark mass dependence. The resulting pressure displays a sizeably reduced sensitivity to variations of the arbitrary renormalization scale as compared to the state-of-the-art NNLO results. This confirms previous NLO investigations that the RGOPT resummation scheme provides improved convergence properties and reduced renormalization scale uncertainties, thus being a promising prescription to improve perturbative QCD at high and mid range baryonic densities.