2018/06/19 by Ilkka Helenius, Helenius, Ilkka
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.1806.07326
openalex publication_date 2018/06/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In ultra-peripheral heavy-ion collisions the nuclei pass with such a large\nimpact parameter that no strong interaction can take place. However, a photon\nemitted by one nucleus can still interact either with the other nucleus or with\na photon from the another nucleus. The former event type corresponds to\nphotoproduction, earlier studied e.g. in electron-proton collisions at HERA,\nbut now with a nuclear target. This provides an unique opportunity to study the\nnuclear modifications of the PDFs with the photo-nuclear processes measured in\nlead-lead collisions at the LHC. Here we present our recent implementation of\nphotoproduction processes in the Pythia 8 general-purpose Monte-Carlo event\ngenerator. The resulting simulations are compared to charged-hadron and dijet\nphotoproduction data from the HERA experiments, and the theoretical\nuncertainties of the framework are studied. We discuss how the relevant part of\nthe photon flux from heavy ions is obtained using the equivalent photon\napproximation and present predictions for photo-nuclear dijet cross section at\nthe LHC. To estimate the potential of this data to further constrain the\nnuclear PDFs, the expected statistical uncertainty based on LHC luminosity is\ncompared to uncertainties in the current nuclear PDF analyses.\n