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Canada Japan Science

Neutrino 'Flip' Discovery Earns Nobel For Japanese, Canadian Researchers 58

Dave Knott writes with news that the 2015 Nobel Prize in physics has been awarded to Takaaki Kajita (of the University of Tokyo in Japan) and Arthur McDonald (of Queens University in Canada), for discovering how neutrinos switch between different "flavours." As the linked BBC article explains: In 1998, Prof Kajita's team reported that neutrinos they had caught, bouncing out of collisions in the Earth's atmosphere, had switched identity: they were a different "flavour" from what those collisions must have released. Then in 2001, the group led by Prof McDonald announced that the neutrinos they were detecting in Ontario, which started out in the Sun, had also "flipped" from their expected identity. This discovery of the particle's wobbly identity had crucial implications. It explained why neutrino detections had not matched the predicted quantities — and it meant that the baffling particles must have a mass. This contradicted the Standard Model of particle physics and changed calculations about the nature of the Universe, including its eternal expansion.
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Neutrino 'Flip' Discovery Earns Nobel For Japanese, Canadian Researchers

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  • by SuiteSisterMary ( 123932 ) <slebrunNO@SPAMgmail.com> on Tuesday October 06, 2015 @09:09AM (#50669629) Journal
    Sorry we hosed up your Standard Model, eh.
    • Well, it wasn't that good anyway.
    • by Roger W Moore ( 538166 ) on Tuesday October 06, 2015 @09:51AM (#50669949) Journal
      While it is physics beyond the Standard Model it is really easy to incorporate it into the model. In fact it makes the leptons more like the quarks in that they now both have a mixing matrix.

      It's fantastic to hear that Art finally won the Nobel though - many of us were wondering how long it would be before he did! It's very well deserved for a discovery which was at least as significant, and far more surprising, than the Higgs.
      • by budgenator ( 254554 ) on Tuesday October 06, 2015 @11:09AM (#50670539) Journal

        I remember Isaac Asimov saying "Either everything we know about particle physics is wrong, or the sun has gone out; therefore the sun has gone out". in regards to neutrino flip.

        • I remember Isaac Asimov saying "Either everything we know about particle physics is wrong, or the sun has gone out; therefore the sun has gone out". in regards to neutrino flip.

          So which was it then? Don't leave us in suspense.

          • Neither, the point is scientific hubris almost always gets bitch slapped by reality;

      • by daknapp ( 156051 )

        It's fantastic to hear that Art finally won the Nobel though - many of us were wondering how long it would be before he did!

        Indeed he does deserve it. His tenacity is legendary. SNO is amazing.

        Oh, and I now feel ever so slightly more important, as he was my thesis advisor.

    • Re:As a Canadian (Score:4, Informative)

      by UnknowingFool ( 672806 ) on Tuesday October 06, 2015 @12:26PM (#50671105)

      Like much of science, discoveries are based on previous work. Starting in the 1960s physicists encountered the solar neutrino problem [wikipedia.org]. Ray Davis in the Homestake Experiment was trying to detect solar neutrinos but was only getting 1/3 of the amount he expected. But he could repeatedly get the same results. Either he was wrong or the Standard Model was wrong. In the 1980s, Masatoshi Koshiba confirmed Davis' results using a different technique with the Kamiokande II. For some reason there were far fewer solar neutrinos than predicted by the Standard Model.

      In 1998, Takaaki Kajita's work at Kamiokande's successor, Super Kamiokande, gave hints at what may be causing the discrepancy. While the results were not conclusive and dealt with muon neutrinos, it suggested that the amount of neutrinos was in agreement with the Standard Model but that they were oscillating or changing into different flavors which previous experiments were not set up to detect. At the Sudbury Neutrino Observatory (SNO) in 1999, Arthur MacDonald and his team were able to confirm that solar neutrinos oscillate.

      For their work, all four men have now received the Nobel Prize because they showed that the Standard Model of physics was wrong about something fundamental. Initial explanations about the discrepancy suggested that physicists were wrong about how the sun (and stellar fusion) works. The physicists were correct; however, they were wrong about the nature of neutrinos. Originally it was thought that neutrinos have no mass but by oscillating, neutrinos must have some mass even it is very, very small.

      • by lgw ( 121541 )

        This work was huge, because it showed that neutrinos move slower than light. The "flip" was an inspired solution to the missing neutrino problem, as it required a string of assumptions that moved away from the "consensus": that neutrinos move slower than light, that they can "spontaneously" change flavor, and do so frequently, which meant assuming that there was some mechanism to allow the flip without the neutrinos interacting with something. Really quite a reach theoretically, but fully justified by the

  • Until Gabor Fekete weighs in on this, I'm unconvinced.
  • You sure the neutrinos, they're not mutating?

  • by Nidi62 ( 1525137 ) on Tuesday October 06, 2015 @09:50AM (#50669939)
    So what exactly does a neutrino taste like?
  • by dlingman ( 1757250 ) on Tuesday October 06, 2015 @10:01AM (#50670061)

    Suddenly sounds a lot more feasible.

  • by Anonymous Coward
    McFlip to be offered soon at McDonald's everywhere.
  • I think this is the original 2001 Slashdot post from SNO (Sudbury Neutrino Observatory) in Sudbury, Ontario. It did not attract much Slashdot discussion at the time.

    http://science.slashdot.org/st... [slashdot.org]

"Stupidity, like virtue, is its own reward" -- William E. Davidsen

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