Probing the energy spectrum of hadrons in proton air interactions at ultrahigh energies through the fluctuations of the muon content of extensive air showers

TL;DR

This paper shows that fluctuations in muon content of extensive air showers can directly probe the hadron energy spectrum in ultra-high-energy cosmic ray interactions, providing insights into energies beyond 100 TeV.

Contribution

It introduces a method to connect muon content fluctuations in air showers with the hadronic energy spectrum at ultra-high energies, highlighting the potential to study hadron interactions beyond current accelerator capabilities.

Findings

Muon fluctuations correlate with first interaction energy distribution.

Subsequent shower stages have a minor impact on muon fluctuations.

Muons serve as a direct probe of hadron spectra at >100 TeV.

Abstract

We demonstrate that the shower-to-shower fluctuations of the muon content of extensive air showers correlate with the fluctuations of a variable of the first interaction of Ultra High Energy Cosmic Rays, which is computed from the fraction of energy carried by the hadrons that sustain the hadronic cascade. The influence of subsequent stages of the shower development is found to play a sub-dominant role. As a consequence, the shower-to-shower distribution of the muon content is a direct probe of the hadron energy spectrum of interactions beyond 100 TeV center of mass energies.