Speaker
Description
Measurements of direct-photon production in heavy-ion collisions allow for unique insight into the space–time evolution of the hot and dense medium. The absence of final-state interactions and the negligible in-medium path length of photons allows the measurement of photons produced in all stages of the collision. The measurement of photon Hanbury Brown–Twiss (HBT) correlations allows to determine the spatial-temporal characteristics of the emitting source.
In this talk, results on direct-photon production and direct-photon HBT correlations in Pb–Pb collisions at $\sqrt{s_{\text{NN}}} = 2.76$ TeV and $\sqrt{s_{\text{NN}}} = 5.02$ TeV will be presented. These include a precise measurement of the direct-photon excess ratio $R_\gamma$ down to low $p_\text{T}$, as well as the extracted direct-photon HBT correlation radii $R_\text{inv}$ and $R_\text{out}$. All measurements are compared to state-of-the-art theoretical calculations incorporating all relevant photon sources.
Furthermore, the current status of analyses based on LHC Run 3 data will be discussed. The enhanced statistics of these data, in comparison to those of LHC Run 2, offer a unique opportunity to investigate the three-dimensional direct-photon HBT correlation function for the first time.
| Is this an experimental talk? | Yes |
|---|---|
| Is this on behalf of a collaboration? | Yes |
| Which collaboration? | ALICE |
| Are you willing to present as a poster if it is not selected for oral presentation? | Yes |