Speaker
Description
Ultra-peripheral collisions (UPCs) in high-energy heavy-ion collisions provide a unique environment to study a wide range of electromagnetic processes, mediated by virtual photons. In Run 3 of the LHC, the ALICE experiment has begun exploring inclusive photonuclear interactions, where a photon interacts with a nucleus, resulting in its breakup, gamma+A --> X. These interactions include both resolved processes, where the photon fluctuates into a hadronic state and undergoes strong interactions, and direct processes, such as photon-gluon fusion leading to e.g. heavy quark or dijet production. The study of these processes extends our understanding of cold nuclear matter effects and probes the nuclear gluon distribution at low Bjorken-x.
This presentation will showcase the latest results from ALICE on inclusive photonuclear interactions, including transverse momentum and rapidity distributions of charged hadrons. Additionally, new insights from open charm photoproduction in UPCs will be highlighted.
To complement this, the most recent results on exclusive vector meson production, a cornerstone of UPC studies, will also be presented. These measurements provide critical tests of quantum chromodynamics (QCD) in the strong-field regime and offer complementary constraints on the nuclear parton distribution functions.
The combination of inclusive and exclusive UPC studies in ALICE enables a comprehensive investigation of photonuclear dynamics in the high-energy regime, paving the way for deeper insights into the structure and interactions of nuclear matter.
