Karlsruhe 2024 – scientific programme

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T: Fachverband Teilchenphysik

T 35: Cosmic rays 4

T 35.2: Talk

Tuesday, March 5, 2024, 16:15–16:30, Geb. 30.22: Lehmann-HS

Tuning of the Pythia 8 hadronic interaction model for UHECR-induced air shower simulations — •Chloé Gaudu for the Pierre-Auger collaboration — Bergische Universität Wuppertal, Gaußstraße 20, 42119 Wuppertal, Germany

Understanding the properties of extensive air showers (EAS) is of prime importance for extracting the characteristics of ultra high-energy cosmic rays (UHECRs) as observed by the Pierre Auger Observatory. Thorough comparisons of EAS measurements and associated simulations are essential to determine the primary energy and, more importantly, the primary mass of UHECRs. Employing state-of-the-art hadronic interaction models, air shower simulations exhibit a muon deficit compared to measurements, referred to as the Muon Puzzle. The largest uncertainties arise from limited knowledge of high-energy hadronic interactions. The Pythia 8 model, well-tailored for Large Hadron Collider experiments, is rarely used in the context of air showers. However, new features in the Angantyr model of Pythia 8 aim an enhancing of hadron-nucleus interaction descriptions, motivating its potential application in air shower studies.

This contribution focuses on studying p_T-integrated identified particle spectra from π⁻ C fixed-target collisions at NA61/SHINE and comparing them to the newest version of Pythia 8. First, the validity of the Angantyr model to describe the experimental datasets is investigated using the RIVET interface. Secondly, a tune of Pythia 8 is discussed, as well as the influence of the fit parameters on muon production in EAS. *Supported by DFG (SFB 1491)

Keywords: muon puzzle; hadronic interactions; forward physics; tuning; analysis