The 2006 Helmut W. Baer Lecture in Physics
was held on Wednesday, April 5, 2006 in 340 West Hall, 4:00 P.M.

Professor Arthur B. McDonald
University Research Chair in Physics
Director, Sudbury Neutrino Observatory
Physics Dept., Queen's University,
Kingston, Ontario, Canada

Professor McDonald's lecture was titled Studying the Universe from 2 km Underground

Lecture Abstract:
By creating a location that is essentially free from radioactive background, sensitive measurements can be performed to test fundamental laws of physics with neutrinos from the Sun, Dark Matter particles left over from the Big Bang and rare forms of radioactivity. The Sudbury Neutrino Observatory (SNO) is a neutrino detector containing 1,000 tons of heavy water and situated 2,000 meters underground in INCO's Creighton Mine near Sudbury, Ontario. SNO has observed neutrinos from the core of Sun and has found clear evidence for neutrino flavor change. This requires modification of the Standard Model for elementary particles and confirms solar model calculations with great accuracy. The underground facility is now being expanded to create a long-term international facility for underground science (SNOLAB), where measurements of Dark Matter, Double Beta Decay and Solar Neutrinos will be performed with the lowest radioactive background available anywhere. The results for SNO and the future scientific program for SNO and SNOLAB will be described.

More information about Professor Arthur B. McDonald:
Arthur McDonald is University Research Chair in Physics at Queens University in Kingston, Ontario, and Director of the Sudbury Neutrino Observatory. He is from Nova Scotia, and received his undergraduate university degrees from Dalhousie University in Halifax and his PhD from Caltech. After twelve years at Canada's Chalk River Laboratories, he moved to Princeton University as a Professor of Physics, and he returned to Canada in 1989 to head the Sudbury Neutrino Observatory project and to teach as a Professor at Queens University. Before taking on SNO and the solar neutrino problem, his research focused on the effects of the weak interaction in hadronic systems. The SNO experiment has led to a raft of discoveries about the nature of neutrino interactions and of solar neutrinos that have helped change our entire understanding of these elusive elementary particles.

For his scientific and overall leadership, Art McDonald has received a number of recognitions including honorary degrees, the Tom W. Bonner Prize from the American Physical Society, the Canadian Association of Physicists Medal for Lifetime Achievement, the Gerhard Herzberg Canada Gold Medal for Science and Engineering, and numerous lectureships including the UK-Canada Rutherford Lectureship for the Royal Society and the Welsh Lectureship at the University of Toronto.