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Should a neutrino be moving slightly slower than c?

  1. Mar 18, 2012 #1
    The ICARUS results evidence that neutrino moves at speed, not faster/slower, but same as c.
    The CERN results seem to be wrong due to some error in the equipment.

    http://arxiv.org/ftp/arxiv/papers/1203/1203.3433.pdf [Broken]

    aren't the neutrinos expected to travel slightly slower than c? (due to slight mass)

    or is the mass (velocity) difference too small to be noticeable, by any experiment?

    c = speed of light/photon

    the photon has zero rest mass. i am assuming that the relativistic mass of the photon is less than that of neutrino.
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Mar 18, 2012 #2


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    The MSW effect says that neutrinos have (some) mass...except there's the loop hole that 1 mass eigenstate of the neutrinos could be 0, so there's that. There are some upper bounds on neutrino masses, but they seem to be extremely extremely light.

    Neutrinos from SN1987A showed that they basically kept their 3 hour head start on the photons over a distance of ~160k light years! This means they travel EXTREMELY close to the speed of light.

    EDIT: I typo'd I should have said 1 mass eigenstate "COULD BE" 0. The MSW effect doesn't say that any of them has to be 0. It does say that not all of them can be 0, however.
  4. Mar 18, 2012 #3
    You're right, they should. But as you say the difference may be incredibly small, especially if you consider that neutrinos from the 1987 supernova arrived at about the same time as light did (apart from the three hour difference which was due to other factors). So my guess is that the slight lag in speed for the neutrinos may be too small to measure with our current technology.

    (BTW, shouldn't this question go into the other neutrino thread?)
  5. Mar 19, 2012 #4


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    Where it's already been answered in posts 750 and 751...
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