15 July 2025 – The European Physical Journal C has accepted for publication a new KM3NeT paper with the title ‘Measurement of the atmospheric νμ flux with six detection units of KM3NeT/ORCA‘.
For the study we used data recorded by the ORCA6 detector between January 2020 and November 2021. Using machine learning classification, we selected 3894 neutrino candidates and estimated the background from atmospheric muons less that 1%. We derived the atmospheric muon-neutrino energy spectrum using an unfolding procedure and found that the measured flux is in agreement with values measured by other experiments and with theoretical predictions.
To date, the ORCA detector has 28 detection units (ORCA28). We expect that our measurement of the atmospheric muon-neutrino flux will improve with more and more ORCA detection units installed.
The paper is available as a preprint at arXiv 2504.09119.
In the figures below the atmospheric muon-neutrino flux measured with ORCA6 as a function of neutrino energy: (a) in comparison with the HKKM14 model; (b) in comparison with the measurements of other experiments.
(a)
(b)