Electromagnetic Probes: Theory and Experiment

TL;DR

This paper reviews the theoretical and experimental progress in understanding electromagnetic probes, like photons and dileptons, in heavy-ion collisions, highlighting their role in revealing properties of hot, dense nuclear matter.

Contribution

It provides an overview of recent developments in modeling and measuring electromagnetic probes, emphasizing the importance of vector-meson spectral functions and their impact on interpreting experimental data.

Findings

Electromagnetic probes reveal temperature and lifetime of the medium.

Photon and dilepton rates depend on vector-meson spectral functions.

Recent results shed light on chiral symmetry restoration.

Abstract

We review the current state of research on electromagnetic probes in the context of heavy-ion collisions. The focus is on thermal photons and dileptons which provide unique insights into the properties of the created hot and dense matter. This review is intended to provide an introductory overview of the topic as well as a discussion of recent theoretical and experimental results. In particular, we discuss the role of vector-meson spectral functions in the calculation of photon and dilepton rates and present recent results obtained from different frameworks. Furthermore, we will highlight the special role of photons and dileptons to provide information on observables such as the temperature, the lifetime, the polarization and the electrical conductivity of the produced medium as well as their use to learn about chiral symmetry restoration and phase transitions.