Abstract: This thesis explores the interdisciplinary role of neutrino physics in probing phenomena beyond the Standard Model (BSM) through three interconnected themes: consolidating the three-flavor oscillation paradigm, investigating BSM physics, and advancing solar neutrino flux measurements. A global analysis of neutrino oscillation data (solar, atmospheric, reactor, accelerator) resolves parameter tensions and refines mixing angles and mass-squared differences, while addressing ambiguities in mass ordering and $\theta_{23}$ octant. BSM studies leverage Borexino and COHERENT data to constrain Non-Standard Interactions (NSI), disentangling electron- and quark-coupled interactions through oscillation and coherent elastic neutrino-nucleus scattering (CE$\nu$NS) measurements. Solar neutrino analyses integrate pp-chain and CNO-cycle flux measurements to test Standard Solar Models (SSM), disfavoring sterile neutrino explanations for the Gallium anomaly and favoring high-metallicity SSM scenarios. By synthesizing oscillation fits, BSM constraints, and astrophysical models, this work demonstrates the incompatibility of 3+1 mixing parameters with solar data and excludes previously viable NSI regions. The results highlight neutrinos as dual probes of particle physics and stellar processes, providing a framework for future experiments targeting mass ordering, CP violation, and dark sector interactions. This thesis underscores the convergence of diverse methodologies—from precision data analysis to theoretical modeling—as essential for advancing fundamental physics and astrophysics.

Tribunal:

President: Thomas Schwetz-Mangold

Secretary: Jordi Salvadó Serra

Vocal: María del Pilar Coloma Escribano

Suplents:

Aldo M. Serenelli

Ivan Esteban Muñoz

Director: María Concepción González García and Michele Maltoni

Tutor: Joan Soto Riera