Electric Conductivity of QCD Matter and Dilepton Spectra in Heavy-Ion Collisions

TL;DR

This paper investigates how the electric conductivity of QCD matter influences dilepton spectra in heavy-ion collisions, aiming to extract this fundamental property from experimental data through a combined theoretical and phenomenological approach.

Contribution

It introduces a model linking electromagnetic spectral functions to dilepton emission, constrained by lattice QCD, to analyze the sensitivity of dilepton spectra to electric conductivity in heavy-ion collisions.

Findings

Low-mass dilepton spectra are sensitive to the electric conductivity of QCD matter.

Disentangling QGP and hadronic contributions helps identify signatures of electric conductivity.

Future high-precision measurements can potentially extract the electric conductivity from dilepton data.

Abstract

The electric conductivity, $\sigma_{\rm el}$, is a fundamental transport coefficient of QCD matter that can be related to the zero-energy limit of the electromagnetic (EM) spectral function at vanishing 3-momentum in the medium. The EM spectral function is also the central quantity to describe the thermal emission rates and pertinent spectra of photon and dilepton radiation in heavy-ion collisions. Employing a model for dilepton rates that combines hadronic many-body theory with nonperturbative QGP emission constrained by lattice-QCD which describes existing dilepton measurements in heavy-ion collisions, we investigate the sensitivity of low-mass dilepton spectra in Pb-Pb collisions at the LHC to $\sigma_{\rm el}$. In particular, we disentangle the contributions from QGP and hadronic emission, and identify signatures that can help to extract $\sigma_{\rm el}$ from high-precision experimental data expected to be attainable with future detector systems at the LHC.