Work

Photo-nuclear collisions in Pythia 8

Year: 2025

Type: conference-paper

Abstract: We present a new extension in Pythia Monte Carlo event generator that allows to simulate the leading contribution in collisions of a real photon and a heavy ion. The model is based on a vector meson dominance (VMD) where a real photon is modelled as a linear combination of different vector-meson states, and an extension of Angantyr, the heavy-ion model in Pythia, that allow simulations of a generic hadron colliding with an ion target. We first verify the VMD implementation by comparing simulations to HERA photoproduction data. Then we present simulated results corresponding to event selection criteria applied in a recent ATLAS analysis for ultra-peripheral Pb-Pb collisions at the LHC. We find that the simulated results are in line with the ATLAS data when accounting for the limited detector efficiency for charged-particle reconstruction. We also consider two-particle correlations and study whether the simulated events reproduce the collective behaviour seen in the ATLAS photon-lead data.

Source: Proceedings of the International Workshop on the Physics of Ultra Peripheral Collisions

DOI: 10.17161/9279nk67

Authors: I. Helenius, M. Utheim

Institutions: University of Jyväskylä, University of Helsinki, Helsinki Institute of Physics

Language: English

Topic: High-Energy Particle Collisions Research

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funder: H2020 European Research Council

Award: Yoctosecond imaging of QCD collectivity using jet observables