First Results from the Sudbury Neutrino Observatory Explain the Missing Solar Neutrinos and Reveal New Neutrino Properties

June 18, 2001 12:15 pm Eastern Daylight Time

The SNO scientists present their first results today in a paper submitted to Physical Review Letters and in presentations at the Canadian Association of Physicists Annual Conference at Victoria, B.C. and at SNO Institutions in the U.S. and the U.K. "It is incredibly exciting, after all the years spent by so many people building SNO, to see such intriguing results coming out of our first data analysis - with so much more to come." says UK Co-spokesman Prof. David Wark of the Rutherford/Appleton Laboratory and the University of Sussex.

The determination that the electron neutrinos from the Sun transform into neutrinos of another type is very important for a full understanding of the Universe at the most microscopic level. This transformation of neutrino types is not allowed in the Standard Model of elementary particles. Theoreticians will be seeking the best way to incorporate this new information about neutrinos into more comprehensive theories.

The direct evidence for solar neutrino transformation also indicates that neutrinos have mass. By combining this with information from previous measurements, it is possible to set an upper limit on the sum of the known neutrino masses. "Even though there is an enormous number of neutrinos in the Universe, the mass limits show that neutrinos make up only a small fraction of the total mass and energy content of the Universe." says Dr. Hamish Robertson, U.S. Co-Spokesman and Professor of Physics at the University of Washington in Seattle.

New Measurements Reported by the Sudbury Neutrino Observatory

September 7, 2003, 11:45 am Eastern Daylight Time

A common table commodity that people sprinkle on their food every day is the main ingredient in new measurements by scientists at the Sudbury Neutrino Observatory (SNO). In a presentation Sunday, September 7, 2003, at TAUP 2003, a major scientific conference in Seattle, Washington, new measurements are reported that strongly confirm the original SNO results announced in 2001 and 2002 that solved the "Solar Neutrino Problem" and go much further in establishing the properties of neutrinos that cause them to change from one type to another in transit to the Earth from the Sun. "We have moved to a precision phase of the measurements," says Queen's University Professor Art McDonald, SNO Project Director through the first two phases of the project. "These measurements are essential to define a new theory of elementary particles required to explain finite neutrino masses and their ability to change types. Some of the simplest proposed theories have already been ruled out."

Andrea T. Hughes - March 2004