Ultra-peripheral collisions: shining light in hadronic colliders

by Jani Penttala (UCLA)

Friday 21 Feb 2025, 16:00 → 17:00 Europe/Zurich

4/2-037 - TH meeting room (CERN)

Collision processes involving protons or heavy nuclei can be characterized by the impact parameter between the colliding particles. When the impact parameter is very large there is no overlap between the colliding nuclei, and hence the interaction cannot happen through the strong interaction. Instead, electromagnetic interaction starts to dominate, and we can understand the process through the emission of quasi-real photons emitted by at least one of the nuclei. These types of processes are called ultraperipheral collisions (UPCs).In this talk, I will give a broad overview on the current status of UPCs and how they can provide complementary information to similar processes such as deep inelastic scattering. I will discuss both photon-photon collisions and photon-nucleus collisions that can occur in UPCs. In particular, I will discuss exclusive vector meson production in photon-nucleus collisions as a tool to understand nuclear modification and as a probe for target geometry in the transverse plane.

cern_upc.pdf