Seasonal variation of atmospheric muons observed in underground detectors

The atmospheric muon flux originates mainly from the decay of charged pions and kaons produced in particle cascades initiated by the interaction of cosmic rays in the atmosphere. Seasonal changes in the density of the upper atmosphere cause variations in the rate of observed muons through the competition between decay and re-interaction of the charged mesons. The observation of this effect is a standard measurement for underground detectors and is a probe of hadronic interactions. The variations are traditionally interpreted in terms of an effective temperature, which combines the atmospheric temperature profile and the muon production profile. In this presentation, we compare different methods to calculate the muon production profile and the effective temperature, focusing on the application to compact underground detectors such as MINOS and OPERA.