This phenomenon, called neutrino oscillation, is possible only if neutrinos 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. Neutrino oscillation is the process by which neutrinos switch between the three primary flavours: electron neutrinos, mu neutrinos and tao neutrinos.
A neutrino puzzle that physicists had wrestled with for decades had been resolved. They found the located within easy reach of Sudbury /Ontariomit Sudbury Neutrino Observatory (SNO) strong evidence that electron neutrinos caused by nuclear fusion inside the sun can change their identity, on its way to Earth by itself.
Neutrinos are the second-most abundant particles in the cosmos, after photons, the particles of light.
For many years, the central enigma with neutrinos was that up to two-thirds fewer of them were detected on Earth than expected.
The prevailing theory was that neutrinos were massless, but experiments carried out separately in underground labs by teams led by Kajita in Japan and McDonald in Canada showed that this was not the case.
“I received the phone call shortly after 5 O’clock my time, this morning, and was awoken to the wonderful news, and it was very surprising but very gratifying as well”, McDonald described first being informed of the award. As about one fourth of world electricity consumption is used for lighting purposes, the LEDs contribute to saving the Earth’s resources, the Nobel Institute had sad.
Neutrinos are minuscule particles created in nuclear reactions, such as in the sun and the stars.
Discoveries by the Nobel physics laureates have bolstered the notion that neutrinos may have protected us all from complete annihilation by tilting the balance between matter and antimatter, said Hitoshi Murayama, director of the Kavli Institute for the Physcis and Mathematics of the Universe at the University of Tokyo.
The prize was shared by Takaaki Kajita of Japan and Arthur B. McDonald of Canada.
According to an official statement issued by the academy, Takaaki, 56, and McDonald, 72, were awarded for their key contributions to the experiments which demonstrated that neutrinos change identities.
Kajita, who initially told a news conference at his university that “my mind has gone completely blank”.
Kajita showed in 1998 that neutrinos captured at the detector underwent a metamorphosis in the atmosphere, the academy said.
Hardly anything can stop them passing; neutrinos are nature’s most elusive elementary particles.
The prize for medicine was awarded on Monday to three scientists for their work in developing drugs to fight parasitic diseases including malaria and elephantiasis.
Nobel week continues on Wednesday with the announcement of the winners of the Nobel Chemistry Prize.