First measurement of atmospheric νμ and ν̄μ flux with the KM3NeT/ARCA telescope

This thesis focuses on the high-energy atmospheric neutrino flux and its measurement with the second-generation neutrino telescope KM3NeT/ARCA, located in the depths of the Mediterranean Sea. Above 100 GeV, the atmospheric flux is known with an uncertainty of the order of 30%. Its precise measurement is crucial, as it also represents the main background for astrophysical neutrino analysis. The aim of this work is to perform the first ever measurement of the atmospheric muon neutrino charged current flux in the energy range between 100 GeV and 100 TeV with KM3NeT/ARCA, with 21 active strings. To achieve this goal, a dedicated event selection strategy based on machine learning techniques is implemented. The flux is then measured through an unfolding procedure. This approach allows the deconvolution of detector effects from the reconstructed energy spectrum, providing an estimate of the true neutrino flux. The final result is compared with different theoretical curves and measurements performed by other neutrino telescope, such as ANTARES and IceCube.