Journal Article/Contribution to a conference proceedings

GSI-2026-00162

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Interplay of prompt and non-prompt photons in photon-triggered jet observables

Sirimanna, C. ; JETSCAPE Collaboration (Corresponding author)GSI*

2025
EDP Sciences Les Ulis

Please use a persistent id in citations: doi:10.1051/epjconf/202533905002  doi:10.15120/GSI-2026-00162

Report No.: arXiv:2507.00905

Abstract: Prompt photons are important yet challenging to observe in relativistic heavy-ion collisions, as they are produced in the early stages and traverse almost the entire QGP medium without interaction. Experimental analyses typically employ isolation cuts, in the hope to identify prompt photons. Most theoretical studies consider only events with actual prompt photons, assuming no contribution from isolated non-prompt photons to reduce computational cost. For the first time, we present a study that compares simulation results generated using inclusive (bremsstrahlung) and prompt-photon events with multiple experimental observables for both p − p and Pb − Pb collisions at 5.02 TeV. Simulations are carried out using the multi-stage JETSCAPE framework tuned to describe the quenching of jets and hadrons. Isolated non-prompt photons are generated in hard photon bremsstrahlung, where the photon is radiated at a sufficient angle to the jet. Several photon triggered jet and jet substructure observables show significant contributions from inclusive photons, yielding an improvement in comparison with experimental data. Novel photon triggered jet substructure observables are also expected to show new structures, yet to be detected in experiment. This effort examines the significance of isolated nonprompt photons using parameters tuned for a simultaneous description of the leading hadron and jet spectrum, and thus provides an independent verification of the multistage evolution framework.

Note: This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (https://creativecommons.org/licenses/by/4.0/).

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Contributing Institute(s):

1. Heiße & Dichte QCD Materie (TES)

Research Program(s):

1. 612 - Cosmic Matter in the Laboratory (POF4-612) (POF4-612)

Experiment(s):

1. no experiment theory work (theory)

Appears in the scientific report 2025

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