Roundup: Two scientists share 2015 Nobel Prize in Physics

The 2015 Nobel Prize in Physics is being shared by Japan's Takaaki Kajita and Canada's Arthur B. McDonald, the Royal Swedish Academy of Sciences announced Tuesday.

They won the prize "for the discovery of neutrino oscillations, which shows that neutrinos have mass," the body said.

In a telephone interview after the announcement, McDonald said getting this phone call at 4 a.m. in the morning was a "very daunting experience." But he emphasized that it was "a group of colleagues who worked together" to accomplish this achievement.

The Nobel Prize in Physics 2015 recognized Kajita and McDonald for their key contributions to experiments demonstrating neutrinos change identities. This metamorphosis requires that neutrinos have mass. "The discovery has changed our understanding of the innermost workings of matter and can prove crucial to our view of the universe," said the statement.

According to the statement, "the discovery led to the far-reaching conclusion that neutrinos, which for a long time were considered massless, must have some mass, however small." And this was a historic discovery for particle physics.

Now the experiments continue and intense activity is underway worldwide in order to capture neutrinos and examine their properties. New discoveries about their deepest secrets are expected to change current understanding of the history, structure and future fate of the universe, according to the statement.

Kajita, born in 1959, is a Japanese citizen. He is now the director of the Institute for Cosmic Ray Research and professor at the University of Tokyo, Japan.

McDonald, born in 1943, is a Canadian citizen and professor emeritus at Queen's University, Canada.

This year's prize is 8 million SEK (about 0.96 million U.S. dollars), which will be shared equally between the two laureates. Endit