Possible non-prompt photons in $pp$ collisions and their effects in $AA$ analyses

Abstract

Direct photons are a powerful tool for elucidating the properties of the hot QCD matter in heavy-ion collisions. They are conventionally estimated by assuming prompt photon contributions in proton-proton collisions and thermal and prompt photon contributions in heavy-ion collisions. On the other hand, there could also be other sources of photons such as pre-equilibrium photons. I investigate prompt, pre-equilibrium and thermal photons and their effects on the direct photon $p_T$ spectra at CERN Large Hadron Collider energies.

Comments: 4 pages, 2 figures - To appear in the conference proceedings for Hard Probes 2018, September 30-October 5, Aix-Les-Bains, France