Inclusive charm photoproduction in ultraperipheral collisions at the LHC

by Anna Stasto (Penn State University)

Friday 25 Jul 2025, 11:00 → 14:00 US/Eastern

CFNS library (https://bnl.zoomgov.com/j/1614715193?pwd=WkwxODVWdzZzb29zQnZRVGp3VTBDQT09)

Ultraperipheral collisions (UPCs) of nuclei at high energies offer unique opportunity to explore the nuclear structure in a clean environment. UPCs occur when two nuclei scatter at impact parameters that exceed the sum of nuclear radii. The UPCs lead to large photonuclear cross sections.  In UPC processes involving jets or heavy quarks, large scale allows for perturbative description of the process, and thus such processes can serve as good probes of the nuclear structure. We present the calculation of the  inclusive D0 production cross section in UPC PbPb collisions at the LHC using the Generalized photon-nucleus FONLL framework. In this approach the heavy quark production is computed using the FONLL framework developed previously by Cacciari-Frixione-Nason for ep collisions,  and includes additional electromagnetic corrections to describe the  photoproduction cross section in UPC heavy ion collisions. The calculations are validated against the D* photoproduction cross section from HERA. The predictions for D0 cross section as a function of rapidity and transverse momentum of the D0 meson are presented and compared to the preliminary results from UPC collisions measured by CMS. The sensitivity of the results is studied, when different choices of parton distribution functions and fragmentation functions are made, as well as a function of variation in renormalization and factorization scale dependence.