Temporal mesonic correlators at NLO for any quark mass

TL;DR

This paper provides next-to-leading order (NLO) calculations of thermal mesonic correlators across different quark masses, comparing theoretical predictions with lattice data and discussing the physics near the quark-antiquark threshold.

Contribution

It offers NLO results for thermal correlators at any quark mass, estimates the validity of non-relativistic approximations, and analyzes discrepancies with lattice data, especially in the scalar channel.

Findings

Good agreement in the vector channel with lattice data.

Substantial discrepancy in the scalar channel explained by threshold physics.

Charm quarks are a borderline case for non-relativistic approximation.

Abstract

We present NLO results for thermal imaginary-time correlators in the vector and scalar channels as a function of the quark mass. The range of quark masses for which a non-relativistic approximation works in the temperature range considered is estimated, and charm quarks turn out to be a borderline case. Comparing with simulation data from fine lattices, we find good agreement in the vector channel but a substantial discrepancy in the scalar one. An explanation for the discrepancy is suggested in terms of physics of the quark-antiquark threshold region. Perturbative predictions for the bottom scalar spectral function around the threshold are also briefly reviewed.