Electric conductivity of QCD matter and dilepton spectra in heavy-ion collisions

The electric conductivity, <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:msub><a:mi>σ</a:mi><a:mi>el</a:mi></a:msub></a:math>, 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 three-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, I investigate the sensitivity of low-mass dilepton spectra in Pb-Pb collisions at the CERN Large Hadron Collider (LHC) to <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:msub><b:mi>σ</b:mi><b:mi>el</b:mi></b:msub></b:math>. In particular, I separately evaluate the contributions from QGP and hadronic emission, and identify signatures that can help to extract <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:msub><c:mi>σ</c:mi><c:mi>el</c:mi></c:msub></c:math> from high-precision experimental data expected to be attainable with future detector systems at the LHC. Published by the American Physical Society 2024