2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/84890A brief description of the path-breaking evidence for the observation of neutrino oscillations at the Sudbury Neutrino Observatory is presented and the experimental principles and theory thereof are briefly discussed.2 pages set in RevTeX4. Errata to Version 1 addedPopular Physicstext