Fermion masses, neutrino oscillations, and proton decay in the light of SuperKamiokande

Within the framework of unified gauge models, interactions responsible for neutrino masses can also provide mechanisms for nucleon instability. We discuss their implications concretely in the light of recent results on neutrino oscillation from the SuperKamiokande collaboration. We construct a predictive SO(10)-based framework that describes the masses and mixing of all quarks and leptons. An overconstrained global fit is obtained, that makes five successful predictions for quarks and charged leptons. The same description provides agreement with the SuperK results on atmospheric neutrinos and supports a small-angle MSW mechanism. We find that current limits on nucleon stability put significant stress on the framework. Further, a distinctive feature of the SO(10) model developed here is the likely prominence of the $\mu^+ K^0$ mode in addition to the $\bar{\nu} K^+$ mode of proton decay. Thus improved searches in these channels for proton decay will either turn up events, or force us outside this circle of ideas.