Monday, 18 July 2022
SR K1-3 (Goldene Box), PI, INF 226

Speaker: Prof. Dr. Ralf Rapp (Texas A&M University, USA)
Title of Talk: Electromagnetic Spectral Function and Thermal Dileptons in Heavy-Ion Collisions

Abstract: Spectral functions of QCD matter are pivotal to understanding fundamental properties of the medium, including its degrees of freedom, transport properties and signals of phase transitions. The only known observable in heavy-ion collisions that directly probe an in-medium spectral function are invariant-mass spectra of dileptons. After a brief overview of theoretical approaches to calculate the electromagnetic spectral function in hot and dense matter, we discuss how they can be used to study the transition from hadronic to quark matter, the restoration of the spontaneously broken chiral symmetry and its relation to hadronic-mass generation, and the electric conductivity as a fundamental transport coefficient of the medium. These considerations will be put into context with existing and future dilepton measurements in nuclear collisions over almost four orders of magnitude in collision energy.