Spectrum and Charge Ratio of Vertical Cosmic Ray Muons up to Momenta of 2.5 TeV/c

TL;DR

This study measures the momentum spectrum and charge ratio of vertical cosmic ray muons up to 2.5 TeV/c underground, providing insights into primary cosmic ray composition and validating air shower models.

Contribution

It presents the first measurement of the cosmic ray muon spectrum and charge ratio at such high momenta using the ALEPH detector, and infers primary cosmic ray properties.

Findings

Cosmic ray muon spectrum extends up to 2.5 TeV/c.

Charge ratio indicates a light primary cosmic ray composition.

Results agree with Monte Carlo air shower models.

Abstract

The ALEPH detector at LEP has been used to measure the momentum spectrum and charge ratio of vertical cosmic ray muons underground. The sea-level cosmic ray muon spectrum for momenta up to 2.5 TeV/c has been obtained by correcting for the overburden of 320 meter water equivalent (mwe). The results are compared with Monte Carlo models for air shower development in the atmosphere. From the analysis of the spectrum the total flux and the spectral index of the cosmic ray primaries is inferred. The charge ratio suggests a dominantly light composition of cosmic ray primaries with energies up to 10^15 eV.