Study of the muon content of very high-energy EAS measured with the KASCADE-Grande observatory

TL;DR

This study measures the muon content of very high-energy extensive air showers using KASCADE-Grande, comparing results with simulations to test hadronic interaction models and identify discrepancies.

Contribution

It provides the first detailed analysis of muon evolution with zenith angle at high energies, highlighting mismatches with current simulation models.

Findings

Observed discrepancies between measurements and MC simulations.

Identified issues with the lateral distribution function of muons.

Results challenge existing hadronic interaction models at high energies.

Abstract

The KASCADE-Grande detector is an air-shower array devoted to the study of primary cosmic rays with very high-energies (E = 10^{16} - 10^{18} eV). The instrument is composed of different particle detector systems suitable for the detailed study of the properties of Extensive Air Showers (EAS) developed by cosmic rays in the atmosphere. Among the EAS observables studied with the detector, the charged number of particles, the muon content (at different energy thresholds), and the number of electrons are found. By comparing the measurements of these air-shower parameters with the expectations from MC simulations, different hadronic interaction models can be tested at the high-energy regime with the KASCADE-Grande experiment. In this work, the results of a study on the evolution of the muon content of EAS with zenith angle, performed with the KASCADE-Grande instrument, is presented. Measurements are compared with predictions from MC simulations based on the QGSJET II, QGSJET II-04, SIBYLL 2.1 and EPOS 1.99 hadronic interaction models. A mismatch between experiment and simulations is observed. A similar problem is found for the evolution of the lateral distribution function of muons in the atmosphere.