Power corrections to the electromagnetic spectral function and the dilepton rate in QCD plasma within operator product expansion in D=4

TL;DR

This paper calculates nonperturbative power corrections to the electromagnetic spectral function in QCD plasma using operator product expansion, revealing an enhanced dilepton production rate in the intermediate mass range.

Contribution

It systematically incorporates leading order power corrections within OPE in D=4, ensuring finite Wilson coefficients and providing a nonperturbative dilepton rate in QCD plasma.

Findings

Power corrections enhance dilepton rate in intermediate mass range.

Operator mixing removes mass singularities, ensuring finite Wilson coefficients.

Results compare favorably with lattice QCD and effective models.

Abstract

We evaluate the electromagnetic spectral function in QCD plasma in a nonperturbative background of in-medium quark and gluon condensates by incorporating the leading order power corrections in a systematic framework within the ambit of the operator product expansion in D=4 dimension. We explicitly show that the mixing of the composite operators removes mass singularities and renders Wilson coefficients finite and well defined. As a spectral property, we then obtain the nonperturbative dilepton production rate from QCD plasma. The operator product expansion automatically restricts the dilepton rate to the intermediate mass range, which is found to be enhanced due to the power corrections. We also compare our result with those from nonperturbative calculations, e.g., lattice QCD and effective QCD models based on Polyakov loop.