Balloon Measurements of Cosmic Ray Muon Spectra in the Atmosphere along with those of Primary Protons and Helium Nuclei over Mid-Latitude

TL;DR

This study presents balloon-based measurements of atmospheric muon spectra and primary cosmic ray protons and helium nuclei, providing data relevant to understanding the atmospheric neutrino anomaly and decoupling various uncertainties.

Contribution

It offers simultaneous measurements of muon and primary cosmic ray spectra in a single experiment, reducing systematic uncertainties and improving the understanding of atmospheric neutrino fluxes.

Findings

Muon spectra measured from 0.3 to 40 GeV/c

Primary proton and helium spectra measured from 3 to 100 GV

Results help clarify the atmospheric neutrino anomaly

Abstract

We report here the measurements of the energy spectra of atmospheric muons and of the cosmic ray primary proton and helium nuclei in a single experiment. These were carried out using the MASS superconducting spectrometer in a balloon flight experiment in 1991. The relevance of these results to the atmospheric neutrino anomaly is emphasized. In particular, this approach allows uncertainties caused by the level of solar modulation, the geomagnetic cut-off of the primaries and possible experimental systematics to be decoupled in the comparison of calculated fluxes of muons to measured muon fluxes. The muon observations cover the momentum and depth ranges of 0.3-40 GeV/c and 5-886 g/cmsquared, respectively. The proton and helium primary measurements cover the rigidity range from 3 to 100 GV, in which both the solar modulation and the geomagnetic cut-off affect the energy spectra at low energies.