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Public Lecture: How to know a neutrino from a hole in the ground

Some people change how we see the world. Dr. Arthur B. McDonald has changed the way we see the universe.

Dr. McDonald was co-recipient of the 2015 Nobel Prize in Physics, together with Takaaki Kajita of the University of Tokyo. His contributions to our understanding of neutrinos—tiny subatomic particles that are one of the fundamental building blocks of the universe—have been instrumental to physicists all over the world.

Dr. McDonald, a Dalhousie alumnus twice over, returned to his alma mater and home province on March 14th, 2016 to share his ground breaking work in a public lecture for the Halifax community.


How to know a neutrino from a hole in the ground
Dr. Arthur B. McDonald, Professor Emeritus, Queen's University

By creating an ultra-clean underground location with a highly reduced radioactive background, otherwise impossible measurements can be performed to study fundamental physics, astrophysics and cosmology. The Sudbury Neutrino Observatory (SNO) was a 1,000 tonne heavy-water-based neutrino detector created 2 km underground in a mine near Sudbury, Canada. SNO found clear evidence for neutrino flavor change that also requires that neutrinos have non-zero mass. This demands modification of the Standard Model for Elementary Particles and confirms solar model calculations with great accuracy. The 2015 Nobel Prize in Physics and the 2016 Breakthrough Prize in Fundamental Physics were awarded for these measurements. Future measurements at the expanded SNOLAB underground science facility will search for Dark Matter particles thought to make up 26% of our Universe and rare forms of radioactivity that can tell us further fundamental properties of neutrinos potentially related to the origin of our matter-dominated Universe.

About Dr. Arthur B. McDonald, Nobel Laureate

Dr. McDonald, originally from Sydney, N.S., earned his Bachelor of Science degree in Physics at Dalhousie in 1964, followed by his Master of Science degree in Physics the subsequent year. He also has an honorary degree from Dalhousie, presented to him in 1997. Dr. McDonald is now a Professor Emeritus at Queen’s University.

Dr. McDonald’s Nobel-recognized research was conducted nearly 15 years ago at Queen’s Sudbury Neutrino Observatory (SNO), located in a mine two kilometres underground. There, his team was able to demonstrate that neutrinos change their identities—or oscillate—on their way to Earth from the sun, a discovery that gave credence to theories that the particles could have a mass greater than zero. Previous experiments had suggested that possibility, but prior to Dr. McDonald no scientist had ever been able to learn enough about the properties of neutrinos to illustrate that.

For his research, Dr. McDonald has also received many of the top scientific honours in Canada and beyond, including a Killam Prize in the Natural Sciences, the Herzberg Canada Gold Medal for Science and Engineering, and the Order of Canada. Recent;y, he was also awarded the 2016 Breakthrough Prize in Fundamental Physics.

Dal News: Dal alum Arthur McDonald wins Nobel Prize in Physics