Measurement of the charge ratio of atmospheric muons with the CMS detector

TL;DR

This paper reports a highly precise measurement of the atmospheric muon charge ratio across a wide momentum range using the CMS detector, confirming models of cosmic ray muon production.

Contribution

It provides the most precise measurement to date of the muon charge ratio below 100 GeV/c and observes an increase at higher momenta, aligning with existing models.

Findings

Charge ratio below 100 GeV/c is 1.2766 +/- 0.0045.

Charge ratio increases at momenta above 100 GeV/c.

Results agree with cosmic ray muon production models.

Abstract

A measurement is presented of the flux ratio of positive and negative muons from cosmic ray interactions in the atmosphere, using data collected by the CMS detector at ground level and in the underground experimental cavern. The excellent performance of the CMS detector allowed detection of muons in the momentum range from 5GeV/c to 1TeV/c. For muon momenta below 100GeV/c the flux ratio is measured to be a constant 1.2766 +/-0.0032(stat.) +/-0.0032(syst.), the most precise measurement to date. At higher momenta an increase in the charge ratio is observed, in agreement with models of muon production in cosmic ray showers and compatible with previous measurements by deep underground experiments.