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Arthur B. McDonald, 2015 Nobel Prize in
Physics
Arthur McDonald, a
professor emeritus at Queen's University in Kingston, Ont., is the
co-winner of the 2015 Nobel Prize in Physics.
McDonald shares the prize with Takaaki Kajita of the University of
Tokyo.
The winners were announced by a committee at the Royal Swedish Academy
of Sciences in Stockholm on Tuesday. McDonald and Kajita will split the
eight million Swedish kronor (almost $1.3 million Cdn) prize.
The academy said the two men won the prize for their contributions to
experiments demonstrating that subatomic particles called neutrinos
change identities, also known as "flavours." The neutrinos transform
themselves between three types: electron-type, muon-type and tau-type.
The metamorphosis requires that neutrinos have mass, dispelling the
long-held notion that they were massless. The academy said the discovery
"has changed our understanding of the innermost workings of matter."
"Yes, there certainly was a Eureka moment in this experiment when we
were able to see that neutrinos appeared to change from one type to the
other in travelling from the Sun to the Earth," McDonald told reporters
by telephone from his home in Kingston.
Neutrinos, along with quarks and electrons, are the most basic particles
that make up matter — "particles that we don't know how to subdivide any
further," McDonald told CBC News in an interview. Among those three
types of basic particles, neutrinos are the hardest to detect.
McDonald managed to study them with a detector the size of a 10-storey
building deep underground at SNOLAB, where most other particles that
could cause false signals can't penetrate.
He added that scientists still want to know what the actual mass of the
neutrino is, and whether there are other types beyond the three
currently known.
McDonald said being named winner is a "very daunting experience,
needless to say."
"Fortunately, I have many colleagues as well who share this prize with
me," he added.
McDonald is retired from teaching, but he is still involved in research.
"In fact, we're just about to turn on an experiment to attempt to
observe particles called dark matter particles. We'll have ten times
better sensitivity than other experiments have had so far...and that may
lead to another Eureka moment, we hope," he said in an interview with
CBC's Heather Hiscox.
Born in Sydney, N.S., in 1943, McDonald earned bachelor's and master's
degrees from Dalhousie University. He got his PhD in physics from
California Institute of Technology in 1969.
He worked for Atomic Energy of Canada from the late 1960s until 1982,
when he moved to Princeton University for seven years.
He has been at Queen's since 1989 and has been a professor emeritus
since 2013.
Learn more at
http://www.cbc.ca/news/technology/nobel-prize-physics-2015-1.3258178
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