Measurement of the atmospheric muon charge ratio with the OPERA detector

TL;DR

This study measures the atmospheric muon charge ratio at TeV energies using the OPERA detector, analyzing a large dataset to understand primary cosmic ray composition and muon production mechanisms.

Contribution

It provides the first detailed measurement of the muon charge ratio at TeV energies with corrections for misidentification and energy-dependent analysis.

Findings

Measured muon charge ratio varies with energy and event type.

Determined pion and kaon charge ratios weighted by cosmic ray spectrum.

Data supports models of muon production in the atmosphere.

Abstract

The OPERA detector at the Gran Sasso underground laboratory (LNGS) was used to measure the atmospheric muon charge ratio in the TeV energy region. We analyzed 403069 atmospheric muons corresponding to 113.4 days of livetime during the 2008 CNGS run. We computed separately the muon charge ratio for single and for multiple muon events in order to select different energy regions of the primary cosmic ray spectrum and to test the charge ratio dependence on the primary composition. The measured charge ratio values were corrected taking into account the charge-misidentification errors. Data have also been grouped in five bins of the "vertical surface energy". A fit to a simplified model of muon production in the atmosphere allowed the determination of the pion and kaon charge ratios weighted by the cosmic ray energy spectrum.