Massive vector current correlator in thermal QCD

TL;DR

This paper provides a next-to-leading order analysis of the massive vector current correlator in thermal QCD, comparing perturbative calculations with lattice data and exploring non-perturbative effects relevant for heavy quark physics.

Contribution

It offers a comprehensive NLO perturbative study of the massive vector current correlator in thermal QCD, including comparisons with lattice data and analysis of non-perturbative modifications.

Findings

Good agreement between NLO perturbation theory and lattice data.

Non-perturbative effects can significantly modify the transport peak.

The study highlights the limitations of effective theories for charm quarks.

Abstract

We present an NLO analysis of the massive vector current correlator at temperatures above a few hundred MeV. The physics of this correlator originates from a transport peak, related to heavy quark diffusion, and from the quark-antiquark threshold, related to quarkonium physics. In the bottom case both can be studied with separate effective theories, but for charm these may not be accurate, so a study within the full theory is needed. Working in imaginary time, the NLO correlator can be computed in unresummed perturbation theory; comparing with lattice data, we find good agreement. Subsequently we inspect how non-perturbative modifications of the transport peak would affect the imaginary-time correlator. The massive NLO quark-number susceptibility is also contrasted with numerical measurement.