Observation of muon intensity variations by season with the MINOS Near Detector

TL;DR

This study analyzes over 1.5 billion cosmic-ray muon events detected underground to investigate how muon intensity varies with atmospheric temperature, finding a strong correlation and quantifying it with specific coefficients.

Contribution

The paper provides the first detailed measurement of the correlation between underground muon rates and atmospheric temperature using the MINOS Near Detector.

Findings

Muon rate correlates strongly with atmospheric temperature.

Determined temperature coefficients for muon flux variations.

Introduced weighted effective temperature to improve modeling.

Abstract

A sample of 1.53$\times$10$^{9}$ cosmic-ray-induced single muon events has been recorded at 225 meters-water-equivalent using the MINOS Near Detector. The underground muon rate is observed to be highly correlated with the effective atmospheric temperature. The coefficient $\alpha_{T}$, relating the change in the muon rate to the change in the vertical effective temperature, is determined to be 0.428$\pm$0.003(stat.)$\pm$0.059(syst.). An alternative description is provided by the weighted effective temperature, introduced to account for the differences in the temperature profile and muon flux as a function of zenith angle. Using the latter estimation of temperature, the coefficient is determined to be 0.352$\pm$0.003(stat.)$\pm$0.046(syst.).