Measurements of the Quasielastic Scattering of Muon Neutrinos on Argon at the Short-Baseline Near Detector

As accelerator-based neutrino experiments enter an era of precision measurements, our limited understanding of the complexities of neutrino-nucleus interactions remains a critical challenge. The Short-Baseline Near Detector (SBND), a liquid argon time projection chamber (LArTPC) at Fermilab, is uniquely positioned to address this challenge by delivering measurements of neutrino-nucleus interactions with unprecedented detail. This dissertation describes the development of artificial intelligence tools for enhanced LArTPC data processing, as well as the inaugural neutrino-nucleus interaction measurement from SBND: the muon neutrino charged-current quasielastic-like (CCQE-like) cross section on argon. The CCQE interaction channel is particularly important, as it is the dominant interaction at SBND neutrino energy region and one of the cleanest final state signatures observed in LArTPCs. However, within a heavy argon nucleus (\(A=40\)), the CCQE signal is complicated by several nuclear effects. This thesis focuses on a well-defined, semi-exclusive final state: exactly one muon, exactly one proton, and no pions, commonly referred to as the ``CCQE-like" topology. Differential cross sections for this channel are extracted by selecting a high-purity sample and applying an unfolding procedure, tested extensively with fake data to ensure stability and systematic robustness. The resulting cross sections reveal that the interaction models used at SBND describe final-state momentum spectra reasonably well, but significant tensions emerge in angular distributions and in observables that are particularly sensitive to nuclear effects. A broad comparison of alternative models shows that no single approach reproduces all features of the measurement, indicating that different variables probe distinct aspects of neutrino-nucleus dynamics. With high statistics, high signal purity, and well-controlled systematic uncertainties, SBND achieves unprecedented sensitivity to these tensions. In summary, this thesis marks a significant milestone for SBND’s cross-section program and establishes an important benchmark for neutrino-argon interaction modeling.