# A new version of the event generator Sibyll

## TL;DR

This paper introduces an improved version of the Sibyll event generator, enhancing its accuracy in simulating hadronic interactions for cosmic ray air showers and atmospheric lepton fluxes based on recent experimental data.

## Contribution

The paper presents a new version of Sibyll with updated physics models and a charm production component, validated against recent collider data.

## Key findings

- Improved agreement with LHC data
- Enhanced predictions for air shower simulations
- Inclusion of charm particle production model

## Abstract

The event generator Sibyll can be used for the simulation of hadronic multiparticle production up to the highest cosmic ray energies. It is optimized for providing an economic description of those aspects of the expected hadronic final states that are needed for the calculation of air showers and atmospheric lepton fluxes. New measurements from fixed target and collider experiments, in particular those at LHC, allow us to test the predictive power of the model version 2.1, which was released more than 10 years ago, and also to identify shortcomings. Based on a detailed comparison of the model predictions with the new data we revisit model assumptions and approximations to obtain an improved version of the interaction model. In addition a phenomenological model for the production of charm particles is implemented as needed for the calculation of prompt lepton fluxes in the energy range of the astrophysical neutrinos recently discovered by IceCube. After giving an overview of the new ideas implemented in Sibyll and discussing how they lead to an improved description of accelerator data, predictions for air showers and atmospheric lepton fluxes are presented.