Abstract

The continuously surprising and peculiar nature of neutrinos and the weak interaction have been a source of puzzlement since they were first discovered. In recent years, a remarkable paradigm has emerged that seeks to explain hidden symmetries, the scale of neutrino masses and the reason for the imbalance between matter and antimatter in the universe. A cornerstone of this includes the notion that the physical neutrinos we see are their own antiparticles. A pioneering new approach to searching for this rare process involves a novel use of the SNO detector in Canada as part of the SNO programme, which has a large UK involvement. In addition, the unique nature of the SNO instrument will allow for the study a remarkable variety of other physics as well. These include the ability to perform precision measurements of solar neutrinos at the transition between matter and vacuum-dominated oscillations to critically test fundamental neutrino couplings; making the first measurement of neutrinos from the CNO cycle to solve the “Solar Composition Problem”; the study of geo-neutrinos, reactor neutrinos and potential supernova neutrinos; and will even provide the most sensitive search for “invisible” modes of nucleon decay.