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Arthur B. McDonald

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description Arthur B. McDonald Overview

Arthur B. McDonald is a Canadian experimental physicist renowned for his leadership of the Sudbury Neutrino Observatory project. His team’s research provided definitive evidence of neutrino oscillations, a fundamental discovery in particle physics that altered our understanding of these subatomic particles. This work earned him the 2015 Nobel Prize in Physics and is particularly relevant to researchers studying neutrinos and their properties, as well as those investigating the universe's earliest moments.

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What did Arthur B. McDonald discover about neutrinos?

McDonald led the Sudbury Neutrino Observatory (SNO) collaboration, which proved that neutrinos produced by the Sun change their flavor as they travel to Earth—a phenomenon called neutrino oscillation. This discovery demonstrated that neutrinos have nonzero mass, overturning the long-held Standard Model assumption that they are massless.

When did Arthur McDonald win the Nobel Prize?

McDonald shared the 2015 Nobel Prize in Physics with Japanese physicist Takaaki Kajita, whose Super-Kamiokande experiment independently confirmed neutrino oscillations using atmospheric neutrinos. The Nobel Committee cited their discovery as having changed our understanding of the innermost workings of matter.

What is the Sudbury Neutrino Observatory?

SNO is a neutrino detector located about 2,100 meters underground in Vale's Creighton Mine near Sudbury, Ontario, Canada. It used 1,000 tons of heavy water on loan from Atomic Energy of Canada Limited, which allowed it to detect all three neutrino flavors through different reaction channels.

What was the solar neutrino problem that McDonald's work solved?

Since the 1960s, Ray Davis's experiments detected only about one-third of the electron neutrinos predicted by solar models, a discrepancy known as the solar neutrino problem. In 2001 and 2002, the SNO collaboration showed that the total number of neutrinos from the Sun matched the prediction—two-thirds had simply changed into other flavors that earlier experiments could not detect.