Overview of the latest ALICE UPC and photonuclear results

TL;DR

This paper reviews recent ALICE experiment results on ultra-peripheral collisions at the LHC, highlighting new measurements of photon-induced processes and interference phenomena, and discusses future prospects with upcoming Run 3 data.

Contribution

It presents the first measurements of K+K- photoproduction and detailed studies of vector meson interference in ultra-peripheral collisions at the LHC.

Findings

First measurement of K+K- photoproduction in UPCs

Observation of vector meson interference effects

Enhanced prospects for UPC studies with Run 3 data

Abstract

Ultra-peripheral collisions (UPC) are events characterised by large impact parameters between the two projectiles, larger than the sum of their radii. In UPCs, the protons and ions accelerated by the LHC do not interact via the strong interaction and can be regarded as sources of quasireal photons. Using the Run 2 data, the ALICE Collaboration has carried out various measurements of different final-state systems, such as exclusive four pion photoproduction as well as photoproduction of $K^+K^-$ pairs, measured for the first time in ultra-peripheral collisions. In addition, vector meson production in Pb--Pb provides the unique opportunity to carry out an analogy of the double-slit experiment at femtometre scales, owing to the interference between the production sources of the two lead nuclei. These results and prospects for UPC measurements using Run 3 data will be presented.