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876Re: Missing Solar Neutrinos

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  • larjsy
    Dec 21, 2001
      > The construction of the SNO Laboratory began in 1990 and was
      > completed in 1998 at a cost of $73M CDN... <snip>

      Beats me how anyone was persuaded that neutrinos were important
      enough to spend that kind of money, plus the ongoing expense of the
      100 staff! -lar

      "And all this science I don't understand ...It's just my job five
      days a week" -Lyrics by Bernie Taupin, Music by Elton John

      --- In CreationTalk@y..., "Chris Ashcraft" <ashcrac@y...> wrote:
      > http://www.sno.phy.queensu.ca/sno/first_results/
      > June 18, 2001 12:15 pm Eastern Daylight Time
      > First Results from the Sudbury Neutrino Observatory Explain the
      > Missing Solar Neutrinos and Reveal New Neutrino Properties
      > Physicists from Canada, the UK and the US are today announcing that
      > their first results provide a solution to a 30-year old mystery- the
      > puzzle of the missing solar neutrinos. The Sudbury Neutrino
      > Observatory (SNO) finds that the solution lies not with the Sun, but
      > with the neutrinos, which change as they travel from the core of the
      > Sun to the Earth.
      > Neutrinos are elementary particles of matter with no electric charge
      > and very little mass. There are three types: the electron-neutrino,
      > the muon-neutrino and the tau-neutrino. Electron-neutrinos, which
      > associated with the familiar electron, are emitted in vast numbers
      > the nuclear reactions that fuel the Sun. Since the early 1970s,
      > several experiments have detected neutrinos arriving on Earth, but
      > they have found only a fraction of the number expected from detailed
      > theories of energy production in the Sun. This meant there was
      > something wrong with either the theories of the Sun, or the
      > understanding of neutrinos.
      > "We now have high confidence that the discrepancy is not caused by
      > problems with the models of the Sun but by changes in the neutrinos
      > themselves as they travel from the core of the Sun to the earth,"
      > Dr. Art McDonald, SNO Project Director and Professor of Physics at
      > Queen's University in Kingston, Ontario. "Earlier measurements had
      > been unable to provide definitive results showing that this
      > transformation from solar electron neutrinos to other types occurs.
      > The new results from SNO, combined with previous work, now reveal
      > transformation clearly, and show that the total number of electron
      > neutrinos produced in the Sun are just as predicted by detailed
      > models."
      > 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,
      > 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,
      > 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
      > of elementary particles. Theoreticians will be seeking the best way
      > incorporate this new information about neutrinos into more
      > comprehensive theories.
      with support from the Natural Sciences
      > and Engineering Research Council of Canada, the National Research
      > Council of Canada, the Northern Ontario Heritage Foundation,
      > Science and Technology Canada, INCO Limited, the United States
      > Department of Energy, and the Particle Physics and Astronomy
      > Council of the UK. The heavy water is on loan from Canada's federal
      > agency AECL with the cooperation of Ontario Power Generation, and
      > unique underground location is provided through the cooperation and
      > support of INCO Limited.
      > Measurements at the SNO Laboratory began in 1999, and the detector
      > been in almost continuous operation since November 1999 when, after
      > period of calibration and testing, its operating parameters were set
      > in their final configuration.
      > Further information about the SNO detector can be found on the SNO
      > Detector page.
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