The Nobel Prize in Physics 2015 was awarded jointly to Takaaki Kajita and Arthur B. McDonald
"for the discovery of neutrino oscillations, which shows that neutrinos have mass" - NOBEL PRIZE WEB SITE
Scientific Background on the Nobel Prize in Physics 2015 NEUTRINO OSCILLATIONS compiled by the Class for Physics of the Royal Swedish Academy of SciencesNEUTRINO OSCILLATIONS compiled by the Class for Physics of the Royal Swedish Academy of Sciences