Interpolation of hard and soft dilepton rates

TL;DR

This paper develops an interpolation method to accurately compute dilepton production rates in a QCD plasma, bridging the gap between NLO calculations and LPM resummation in the soft mass regime.

Contribution

It introduces a novel interpolation technique combining NLO and LPM results for dilepton rates in QCD plasmas.

Findings

Provides tabulated dilepton rate data for hydrodynamical models.

Addresses the breakdown of loop expansion at soft invariant masses.

Enables more accurate modeling of dilepton production in high-temperature plasmas.

Abstract

Strict next-to-leading order (NLO) results for the dilepton production rate from a QCD plasma at temperatures above a few hundred MeV suffer from a breakdown of the loop expansion in the regime of soft invariant masses M^2 << (pi T)^2. In this regime an LPM resummation is needed for obtaining the correct leading-order result. We show how to construct an interpolation between the hard NLO and the leading-order LPM expression. The final numerical results are presented in a tabulated form, suitable for insertion into hydrodynamical codes.