Speaker
Description
Direct photon measurements provide essential insights into the properties and evolution of the quark-gluon plasma (QGP), from the early initial conditions through the pre-equilibrium stage to the QGP and hadronic phases. In the ALICE experiment, photons are reconstructed using two complementary methods: the photon conversion method, making use of the excellent tracking capabilities of ALICE, and the use of one of the two calorimeters. These techniques enable photon detection across a broad transverse momentum range from 0.4 GeV/$c$, where thermal photons dominate, to several GeV/c, where prompt photon production becomes significant.
This talk will present measurements of direct photon production across different centrality classes in Pb--Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ and $5.02~$TeV. Additionally, we will show the first significant results on direct-photon HBT correlations at low momentum, extending the direct photon measurement down to $p_{\rm T}$ = 0.25 GeV/$c$ and offering new insights into the space-time evolution of the emitting source. Finally, preliminary results from photon reconstruction in LHC Run 3 data will also be discussed.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | ALICE |
