What's old and what's new about neutrinos

To save the laws of conservation of energy, linear and angular momentum, Pauli suggested the possible existence of an elementary particle possessing no electric charge and very little mass called the neutrino, which was emitted in β-decay of the nuclei. Subsequent work over the decades has proved the existence of this particle and has proved its importance not only to the physics of elementary particles but also to astrophysics and cosmology. This article is triggered by the recent experiments which show that the neutrinos of one flavour, as they speed through space, periodically transmogrify onto other flavours. This discovery is comparable to the discovery of the electron in that it provides the basis to new physics beyond the currently accepted Standard Model.