The Standard Model of particle physics, despite its remarkable success, leaves several fundamental questions unanswered, including the origin of the baryon asymmetry of the Universe, neutrino masses and the flavour structure of new physics. This thesis studies baryon-number violation (BNV) as a probe of physics beyond the Standard Model, with particular emphasis on effective field theory, flavour symmetries and connections with neutrino masses. Concerning |Delta B|=1 processes, we study nucleon decay within the Standard Model Effective Field Theory, including correlations among decay channels, and investigate scenarios relating proton decay to radiative Majorana neutrino masses. We further explore |\Delta B|=2 processes beyond neutron–antineutron oscillations, including strange-baryon oscillations and dinucleon decay. Finally, we analyse how flavour symmetries constrain BNV operators and correlate different nucleon-decay channels. Overall, this thesis develops a common framework to connect high-scale baryon-number-violating physics with low-energy observables.
Contracte Predoctoral CIACIF/2021/061
