A new version of the event generator Sibyll

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.

Tests of the SIBYLL 2.3 high-energy hadronic interaction model using the KASCADE-Grande muon data

“…Finally, low energy events, which have poor reconstructed muon numbers, were removed from the data sample by requiring showers that activated more than 11 Grande stations and had a high N µ number (specifically 3 × 10 4 and 4 × 10 4 for data with θ 30 • and 30 • θ < 40 • , respectively). Using the above selection cuts, we got an experimental sample with about 1.24 × 10 7 events and an effective time of ∆t = 1.6 × 10 8 s. On the other hand, the MC simulations were built using SIBYLL 2.3 [2] and Fluka 2011.2 [6] as high-and low-energy (E h ≤ 200 GeV) hadronic interaction models, respectively. The production and development of the shower were simulated with CORSIKA 7.5 [7], while the response of the detector to the passage of the shower, with a GEANT 3.21 [8] based program.…”

“…Recently, a lot of progress has been done towards the reduction of such uncertainties motivated, in part, by the results of the measurements of the LHC [1]. In this regard, one of the models that has been updated is SIBYLL [2].…”

Ultra-High Energy Air Shower Simulation without Thinning in CORSIKA

“…Other new features in CORSIKA include a new version of the hadronic interaction model SIBYLL which now includes charm production [9], which is particularly important for high energy neutrino production. With the new ICECUBE option it is now possible to stop a shower simulation as soon as there is no chance to produce high energy neutrinos in this particular event.…”

Phenomenology of atmospheric neutrinos

“…Muon neutrinos exhibit a pronounced shift towards lower x above 100 TeV, where prompt neutrinos dominate. They are sensitive to the production properties of charmed mesons which are predicted to be distributed more centrally in Sibyll-2.3 [8,9]. These results are model dependent and by exchanging the interaction model some shifts in the importance of x-ranges can be observed.…”