Speaker
Description
High-energy atmospheric muon neutrinos are detected by the IceCube Neutrino Observatory with a high rate of almost a hundred thousand events per year. Being mainly produced in meson decays in cosmic-ray-induced air showers in the upper atmosphere, the flux of these neutrinos is expected to depend on atmospheric conditions and thus features a seasonal variation. The magnitude of this effect can be described with a correlation coefficient ⍺, whose previous measurement with 6 years of IceCube data indicated a discrepancy to theoretical expectations. In this work, we present an update of the previous analysis, extending the statistics to 12-years of IceCube data, as well as adding the northern hemisphere to the analysis. We estimate the correlation coefficient in the southern hemisphere to be ⍺=0.325±0.022, which confirms the previous observation of the tension between the theoretical predictions and experimental measurements with significance >3σ. Furthermore, the seasonal variation in the northern hemisphere has also been observed for the first time, with ⍺=0.731±0.222. Investigations into systematic effects reveal that the observations not only show a weaker correlation compared to the predictions, but also deviate from the expected linear relation between the atmospheric neutrino flux and the atmospheric temperature.
| Collaboration(s) | IceCube |
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