Analysis of the muon neutrino disappearance channel in ICARUS

This thesis presents a preliminary search for muon neutrino disappearance in the Booster Neutrino Beam (BNB) at Fermilab using the ICARUS detector, the far component of the Short Baseline Neutrino Program. The analysis is performed on 10% of the data collected during the ICARUS Run 2 (2022–2023). Events reconstructed as charged-current muon neutrino interactions on argon nuclei that produce a muon and at least one proton in the final state have been selected. The observed reconstructed energy spectrum is compared to a simulation-based prediction within a two-neutrino oscillation framework corresponding to the 3+1 sterile neutrino model. A shape-only analysis is performed including systematic uncertainties associated with the neutrino flux, interaction modeling, and detector response. No evidence for muon neutrino disappearance is observed within the explored parameter space. Exclusion contours at 99% and 99.9% C.L. in the two-dimensional oscillation parameter space (squared mass difference and mixing amplitude) are presented. The sensitivity is limited by systematic uncertainties and is dominated by detector, flux and neutrino interaction model contributions. Future joint analyses combining full data from Far and Near detectors are expected to significantly reduce these uncertainties and improve the sensitivity to sterile neutrino oscillations.