Probing Beyond the Standard Model Scenarios in Long-baseline and Astrophysical Neutrino Experiments

Over the past few decades, outstanding progress in the neutrino experiment frontier has greatly advanced our understanding of the flavor oscillations of active neutrinos. The remaining key questions such as the neutrino mass ordering, the presence of CP violation in the lepton sector, and the octant of $θ_{23}$ are expected to be resolved in the coming years. The current precise knowledge of neutrino mass and mixing parameters, together with the promising prospects of next-generation neutrino experiments, provides a unique opportunity to test scenarios beyond the Standard Model (BSM) through neutrino oscillation phenomena. This thesis investigates several such BSM scenarios and examines the capability of the next-generation neutrino experiments to probe them.