12th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions

Direct photon production and correlations at low $p_{\rm{T}}$ in Pb--Pb collisions with ALICE

24 Sept 2024, 10:50

20m

Room 107

Oral presentation 4. Electromagnetic and electroweak probes Parallel Session 16

Speaker

Dmitri Peresunko (National Research Centre Kurchatov Institute (RU))

Description

Measurements of direct photons can provide valuable information on the properties and evolution of the quark-gluon plasma (QGP); from the initial conditions to the pre-equilibrium, QGP, and the hadronic phase. In the ALICE experiment, photons that convert in the detector material are reconstructed down to low momentum using the excellent tracking capabilities. Furthermore, photons are reconstructed using the calorimeters. Using these methods we can measure the direct-photon production from a transverse momentum of 0.4 GeV/c, where thermal direct photons dominate, up to several GeV/c, where prompt photons take over.
In this talk we will present measurements in selected centrality classes of the direct-photon production in Pb—Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ and $5.02$ TeV, as well as first significant results on direct-photon HBT at low momentum. Finally, the first results on photon reconstruction using LHC Run 3 data will be reported.