Two scientists from Canada and Japan have won the 2015 Nobel Prize in Physics 2015 for opening "a new realm in particle physics," the Nobel Prize committee says. Working far apart, both Takaaki Kajita and Arthur B. McDonald showed how neutrinos shift identities like chameleons in space.The revelation that neutrinos — the subatomic particles that are more numerous than any other in the universe except for particles of light — undergo a metamorphosis led to a second and shocking conclusion: that they have mass.
With that discovery, Kajita and McDonald changed the field of particle physics, which had for years held that neutrinos, which rarely interact with matter, have no mass.
The discoveries about a fundamental and yet mysterious particle were made in two huge physics labs that were built deep underground — one in an old nickel mine in Canada and the other in an abandoned mineral mine in Japan. At depths of a kilometer or more, thousands of sensors at each facility are shielded from cosmic rays, allowing them to focus on detecting neutrinos' behavior.