13 October 2015
The 2015 Nobel Prize in Physics has been awarded to Arthur McDonald and Takaaki Kajita for the discovery of neutrino oscillations. This research field started at the end of the 60’s with the first surprising measurements of the flux of neutrinos produced by the sun. Bruno Pontecorvo suggested then that the observed deficit of solar neutrinos could be due to the periodical transformation among different neutrino flavors (i.e. the type of neutrino) along the travel path to the earth. This phenomenon, called neutrino oscillations, implies that neutrinos are massive particles and that neutrino mass eigenstates do not coincide with the 3 weak interaction eigenstates but are instead a mixture of them.