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Incoming links: Arthur B. McDonald
Arthur B. McDonald Created 2026-10-18 Updated 2026-11-05
Arthur B. McDonald led work at the Sudbury Neutrino Observatory, which distinguished a change of neutrino flavor from a low total solar neutrino flux. Reactions on deuterium provided different flavor sensitivities: the charged-current channel selected electron neutrinos, while the neutral-current channel measured all active neutrino flavors. Their comparison revealed a non-electron component while the total flux agreed with solar expectations. The detector thereby tested the solar neutrino problem without requiring all missing electron-flavor events to mean missing solar production.[ref]
A physicist working in experimental particle astrophysics.[ref]
Arthur McDonald by Queen’s University. Independent professional identity
Portrait of Arthur B. McDonald
. Holger Motzkau, 2015, Wikipedia/Wikimedia Commons; photograph at the Royal Swedish Academy of Sciences press conference, 7 December 2015. Creative Commons Attribution-Share Alike 3.0 Unported., via Wikimedia Commons. Source.
How can a detector establish that an unseen particle changes identity? The Super-Kamiokande atmospheric-neutrino experiment compares different travel paths; the Sudbury Neutrino Observatory compares different interaction channels. Both infer neutrino flavor from reaction products and calibrated responses. Their complementarity connects particle detection to neutrino oscillation, neutrino mass and neutrino astronomy.
Takaaki Kajita and Arthur B. McDonald shared the 2015 physics Nobel Prize. These were collaboration achievements: Yoichiro Suzuki's Super-Kamiokande work included the solar neutrino analysis, and George Ewan helped establish and lead the Sudbury Neutrino Observatory.[ref]
ICRR’s Takaaki Kajita to share Breakthrough Prize in Fundamental Physics by Institute for Cosmic Ray Research, University of Tokyo. Research contributions of Kajita and Suzuki; shared 2015 prize
[ref]https://www.queensu.ca/gazette/stories/queen-s-remembers-professor-emeritus-george-ewan/. 17 December 2020: founding and joint leadership of SNO
The older Kamiokande account explains water Cherenkov neutrino reconstruction; Raymond Davis Jr.'s Homestake experiment explains why a deficit in an electron neutrino channel alone leaves a source-versus-propagation ambiguity. Complementary channels can break that ambiguity.
Nobel Prize in Physics in 2015 2026-10-18
Awarded in equal shares to Takaaki Kajita and Arthur B. McDonald for discovering neutrino oscillations, showing that neutrinos have mass.[ref]
The Nobel Prize in Physics 2015 by Nobel Prize Outreach. Individual official summary: Kajita and McDonald one half each; neutrino oscillations establish neutrino mass.