The LHC as a photon-nucleus factory to characterize cold nuclear matter at high gluonic densities

Only a small fraction of the collisions between ultra-relativistic heavy ions at the Large Hadron Collider (LHC) involve direct strong interactions between the nucleons of the colliding nuclei. In most events, the nuclei interact via their electromagnetic fields in so-called ultra-peripheral collisions (UPCs), which generate an abundant rate of photon-nucleus and photon-photon collisions at the highest center-of-mass energies achievable at colliders. In this seminar, I will highlight how photon-nucleus events in UPCs can serve as a novel tool to probe the dynamics of gluons and quarks in nuclei, particularly in the small Bjorken-x regime. I will discuss recent experimental developments that have transformed the CMS detector into a high-performance detector for studying heavy-flavor and jet production in UPCs. The seminar will include results from the first measurements of the open-charm output in photonuclear collisions, and provide insights into the prospects for future analyses in LHC Run 3/4 and at the future electron-ion collider (EIC).