Dilepton production spectrum above Tc with a lattice quark propagator

TL;DR

This paper investigates dilepton production in a deconfined medium above the critical temperature using lattice-derived quark propagators, revealing significant enhancements and singularities not captured by perturbative methods.

Contribution

It introduces a nonperturbative approach to calculate dilepton rates using lattice QCD quark propagators and the Schwinger-Dyson equation, highlighting effects beyond perturbation theory.

Findings

Dilepton rate shows divergences due to van Hove singularity.

Rate is significantly enhanced around a0T compared to perturbative results.

Enhanced dilepton production indicates strong medium effects above Tc.

Abstract

The dilepton production rate from the deconfined medium is analyzed with the photon self-energies constructed from quark propagators obtained by lattice numerical simulation for two values of temperature $T=1.5T_{\rm c}$ and $3T_{\rm c}$ above the critical temperature $T_{\rm c}$. The photon self-energy is calculated by the Schwinger-Dyson equation with the lattice quark propagtor and a vertex function determined so as to satisfy the Ward-Takahashi identity. The obtained dilepton production rate at zero momentum exhibits divergences reflecting van Hove singularity, and is significantly enhanced around $\omega\simeq T$ compared with the rate obtained by the perturbative analysis.