Photon and dilepton observables: An experimental overview

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.

7 pages, 4 figures, proceedings for plenary talk at Quark Matter 2017, to be published in Nuclear Physics A

References in corpus (2)

• Evidence for radial flow of thermal dileptons in high-energy nuclear collisions
• Measurements of $e^{+}{e}^{-}$ pairs from open heavy flavor in $p$+$p$ and $d$+$A$ collisions at $\sqrt{s_{NN}}=200$ GeV

Cited by in corpus (4)

• Dilepton production and elliptic flow from an anisotropic quark-gluon plasma
• Electric conductivity in finite-density SU(2) lattice gauge theory with dynamical fermions
• Euclidean correlators at imaginary spatial momentum and their relation to the thermal photon emission rate
• Direct photon spectrum and elliptic flow produced from Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV at the CERN Large Hadron Collider within an integrated hydrokinetic model