# Photon and dilepton observables: An experimental overview

## TL;DR

This paper reviews recent experimental results on dilepton and photon production in heavy ion collisions, highlighting excesses and anisotropies that shed light on the early collision stages and the properties of the quark-gluon plasma.

## Contribution

It provides a comprehensive overview of new dilepton and photon measurements from 2017, contextualizing their implications for understanding electromagnetic probes in heavy ion physics.

## Key findings

- Observation of dilepton excess consistent with rho meson broadening
- Detection of low pT photon excess with large azimuthal anisotropy
- Results contribute to understanding the early stages of heavy ion collisions

## Abstract

Dilepton and direct photon measurements in heavy ion collisions provide access to the early stages of the collision. Dilepton continuum measurements at SPS and RHIC show an excess consistent with broadening of the rho meson spectral function as a result of hadronic interactions. Direct photon measurements at RHIC and the LHC show an excess of low $p_{T}$ photons over the expected yield. This excess has a large azimuthal anisotropy with respect to the collision plane. Understanding the direct photon excess and its anisotropy has become an outstanding question in the field of heavy ion physics. This proceeding consists of a summary of new dilepton and direct photon experimental results shown at the 2017 International Conference on Ultrarelativistic Nucleus-Nucleus Collisions and presents them in the context of our current understanding of these electromagentic probes.