Nobel for solving puzzle of elusive neutrino particles

Stockholm/London: A Japanese and a Canadian scientist won the 2015 Nobel Prize for Physics on Tuesday for discovering that elusive subatomic particles called neutrinos have mass, opening a new window onto the fundamental nature of the universe.

Neutrinos are the second most bountiful particles after photons, the particles of light, with trillions of them streaming through our bodies every second, but their true nature has been poorly understood.

Takaaki Kajita and Arthur McDonald's breakthrough was the discovery of a phenomenon called neutrino oscillation that has upended scientific thinking and promises to change understanding about the history and future fate of the cosmos.

“It is a discovery that will change the books in physics, so it is really major discovery,” Barbro Asman, a Nobel committee member and professor of physics at Stockholm University, told Reuters.

In awarding the prize, the Royal Swedish Academy of Sciences said the finding had "changed our understanding of the innermost workings of matter and can prove crucial to our view of the universe".

For many years, the central enigma with neutrinos was that up to two-thirds fewer of them were detected on Earth than expected.

Kajita and McDonald, using different experiments, managed to explain this around the turn of the millennium by showing that neutrinos actually changed identities, or "flavours", and therefore must have some mass, however small.