The Nobel Prize in Physics 2015 recognized Kajita and McDonald for their key contributions to experiments demonstrating neutrinos change identities. The new findings have actually changed our understanding of the innermost workings of matter and are crucial to our view of the universe.
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Kajita showed in 1998 that neutrinos captured at the Super-Kamiokande detector in Japan underwent a metamorphosis in the atmosphere, the academy said.
McDonald, who headed up the neutrino experiment from 1989 to 2007, and his ragtag group of physicists were somehow able to borrow $300 million worth of heavy water – used in Canada’s Candu nuclear reactors for 10 years – for just $1 from the Atomic Energy Canada Limited, he said in an interview.
This shape-shifting property of the mysterious particles proved that neutrinos have mass, the Nobel committee explained in its announcement of the award for the scientists’ work on what it called “nature’s most elusive elementary particles”. There were up to two thirds of neutrinos missing in measurements performed on Earth, compared to theoretical calculations. Together with Professor Arthur B. McDonald, the duo received the Nobel honor for their “discovery of neutrino oscillations, which shows that neutrinos have mass”. The neutrino had always been assumed to have no mass, so this one of those discoveries that’s going to change how we see the universe.
Takaaki Kajita, director of the University of Tokyo’s Institute for Cosmic Ray Research, gestures during a news conference in Tokyo October 6, 2015.
Previous winners of the Nobel Prize for Physics include Albert Einstein, Niels Bohr, Werner Heisenberg and Marie Curie. Before their work, most researchers assumed that neutrinos had no mass-primarily because they pass like ghosts through matter and seem to move near the speed of light. And ongoing experiments are delving into whether there are other types of neutrinos beyond the three clearly observed.
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. It helps to go that deep to measure neutrinos as they stream through the universe, otherwise signal “clutter” from other sources makes them exceedingly hard to trace.
Neutrinos are “particles that we don’t know how to subdivide any further,” McDonald said.
The Nobel Prizes are given by The Royal Swedish Academy of Sciences’. They have no charge and are created in reactions between cosmic radiation and the Earth’s atmosphere, and by nuclear reactions in the Sunday.
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Hopefully, a few of them will come from Nova Scotia, inspired by Arthur McDonald’s example of excellence in the pursuit of basic science and our understanding of the universe.
