QCD mesonic screening masses up to high temperatures

TL;DR

This paper uses lattice Monte Carlo simulations to study QCD mesonic screening masses at very high temperatures, revealing chiral symmetry restoration and discrepancies with perturbative predictions up to 160 GeV.

Contribution

It presents the first non-perturbative lattice results for mesonic screening masses in high-temperature QCD up to 160 GeV, highlighting the limitations of perturbative theories.

Findings

Chiral symmetry restoration evidenced by degeneracy of certain mesonic channels.

Persistent splitting between vector and pseudoscalar screening masses.

Perturbative one-loop predictions do not match non-perturbative data at high temperatures.

Abstract

We discuss a strategy to study non-perturbatively QCD up to very high temperatures by Monte Carlo simulations on the lattice. It allows not only the thermodynamic properties of the theory but also other interesting thermal features to be investigated. As a first concrete application, we compute the flavour non-singlet mesonic screening masses and we present the results of Monte Carlo simulations at 12 temperatures covering the range from T $\sim$ 1 GeV up to $\sim$ 160 GeV in the theory with three massless quarks. On the one side, chiral symmetry restoration manifests itself in our results through the degeneracy of the vector and the axial vector channels and of the scalar and the pseudoscalar ones, and, on the other side, we observe a clear splitting between the vector and the pseudoscalar screening masses up to the highest investigated temperature. A comparison with the high-temperature effective theory shows that the known one-loop order in the perturbative expansion does not provide a satisfactory description of the non-perturbative data up to the highest temperature considered.