Spectrum of cosmic-ray nucleons and the atmospheric muon charge ratio

TL;DR

This paper models the cosmic-ray nucleon spectra and atmospheric muon charge ratio by using recent cosmic-ray data to improve understanding of particle production processes and their implications for neutrino spectra.

Contribution

It introduces a method to estimate proton and neutron spectra separately and calculates the muon charge ratio, enhancing the interpretation of cosmic-ray and atmospheric muon measurements.

Findings

Calculated muon charge ratio matches recent experimental data.

Determined the relative contributions of pions and kaons to muon production.

Discussed implications for muon neutrino spectra.

Abstract

Interpretation of measurements of the muon charge ratio in the TeV range depends on the spectra of protons and neutrons in the primary cosmic radiation and on the inclusive cross sections for production of $\pi^\pm$ and $K^\pm$ in the atmosphere. Recent measurements of the spectra of cosmic-ray nuclei are used here to estimate separately the energy spectra of protons and neutrons and hence to calculate the charge separated hadronic cascade in the atmosphere. From the corresponding production spectra of $\mu^+$ and $\mu^-$ the $\mu^+/\mu^-$ ratio is calculated and compared to recent measurements. The comparison leads to a determination of the relative contribution of kaons and pions. Implications for the spectra of $\nu_\mu$ and $\bar{\nu}_\mu$ are discussed.