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Thread: Massless Neutrino Oscillations

  1. #1
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    Massless Neutrino Oscillations

    Massless Neutrino Oscillations

    In the arxiv there is this approach to the problem of light speed neutrinos that oscillate:

    Massless Neutrino Oscillations via Quantum Tunneling

    http://arxiv.org/abs/1502.00691

    One needs an energy difference to oscillate and the usual prescription is to consider each neutrino flavor to have a different rest mass. But a rest mass prohibits light speed while massless particles move at light speed. Here consideration is given to tunneling through barriers that differ in their energy potentials to give the energy difference so that neutrinos can still oscillate without themselves having the need to have a rest mass.

    Questions as to why there are just three barriers, no more or less, and how the barriers come into being and have the magnitude they have to produce their potentials are not addressed in this paper but are left outstanding for further consideration.

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    Quote Originally Posted by borman View Post
    Questions as to why there are just three barriers, no more or less, and how the barriers come into being and have the magnitude they have to produce their potentials are not addressed in this paper but are left outstanding for further consideration.
    It is an interesting analysis but it does raise some questions that are not addressed including why there are three barriers, why they are highly asymmetric (different mass eigenstates neatly capture this behaviour) and what this means for energy spectra observations of interactions involving different flavour states. While it does simplify some things it seems to introduce some very strange and unique things for neutrinos, in essence they become almost a unique family of particles rather than just weakly interacting uncharged leptons. Although in fairness the mismatch of mass and flavour eigenstates already make them a little odd. It is interesting to see new approaches to this puzzle though.

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    The number 3 is so pervasive in the Standard Model that it is difficult to accept it as a mere multiple coincidence. The refreshing approach of this author to appeal to quantum tunneling allows consideration that the number 3 may be attributed to the properties of the barriers rather than an intrinsic property of the particles. Could not the same presence of barriers have a bearing on sub light speed particles, or massive particles, as well as for massless particles? Is the number 3 beneath all families of particles, not just neutrinos, a possible attribute of an undelying geometry responsible for the barriers? This paper may be "letting the cat out of the bag" for this type of inquiry.

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    Quote Originally Posted by borman View Post
    The number 3 is so pervasive in the Standard Model that it is difficult to accept it as a mere multiple coincidence. The refreshing approach of this author to appeal to quantum tunneling allows consideration that the number 3 may be attributed to the properties of the barriers rather than an intrinsic property of the particles. Could not the same presence of barriers have a bearing on sub light speed particles, or massive particles, as well as for massless particles? Is the number 3 beneath all families of particles, not just neutrinos, a possible attribute of an undelying geometry responsible for the barriers? This paper may be "letting the cat out of the bag" for this type of inquiry.
    That is a rather circular argument. They propose 3 different asymmetric barriers because there are 3 neutrino flavours observed to oscillate. They certainly don't predict the number or provide any relationship between the barriers. And they don't show that these barriers exist for quarks, nor that oscillations happen for them. So I think your speculations are a huge leap from what the paper says, not one I could honestly see any justification for.

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    This is just a very basic question, but it neutrinos were able to oscillate even with zero mass, then why can't photons?
    As above, so below

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    Quote Originally Posted by Jens View Post
    This is just a very basic question, but it neutrinos were able to oscillate even with zero mass, then why can't photons?
    Massless neutrinos cannot oscillate in the current model. The driving term for the oscillation is related to the mass difference between the states.

    As for photons (ignoring the massless problem) - they don't have anything to oscillate into, essentially. The current model for neutrino oscillations is that there are 3 mass states and 3 flavour states and that these are not quite aligned, meaning that as the neutrino oscillated the phase associated with each eigenstate advances at a different rate. Thus you see oscillations.

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    Quote Originally Posted by Jens View Post
    This is just a very basic question, but it neutrinos were able to oscillate even with zero mass, then why can't photons?
    Yes, I considered this question also. Photons are not monitored to oscillate through 3 colors while intransit. So under this author's premise, neutrinos are seeing barriers that photons do not. This can be treated a a clue. Photons may suffer a constraint that does not permit them to see the barriers. They are constrained to follow the null geodesics of the 3+1 brane.

    Also there should be pointed out an isotropy challenge with regard to the barriers: Whatever the time of day, wherever the Earth's orbit and the sun's orbit in the galaxy, wherever the neutrino beams are pointed, the oscillation is confirmed. That is, there is no prefered direction. The barriers are equally everywhere rather than being localised in most experiments where the quantum well can be defined. This is something of a topological puzzle.

    One approach to resolution is to consider that E=m(x/t)^2/2. When there is delta E to accomodate each of the three barriers, then something on the right side of the equation has to delta as well. If it can't be the mass, since light speed particles can't decay according to special relativity, and there is spatial isotropy from observations of neutriino oscillations making delta x unlikely, that leaves us with delta t. Here photons only can see the one t of (3+1), so don't oscillate. But if neutrinos can see three t's, conditions for different energy barriers is satisfied and they can oscillate while having no rest mass and move at light speed.

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    Looking for a smoking gun
    NASA's Hubble discovers four images of same supernova split by cosmic lens
    http://www.eurekalert.org/pub_releas...-nhd030615.php

    They expect another image of this cosmic lens supernova in the not too distant future.
    The recent nearby supernova of 1987 had the neutrinos arrive in advance of the photons. If photons travel faster than neutrinos because neutrinos might have rest mass, then the photons from this very distant supernova will have time to catch up to and possibly overtake the neutrino pulse that presages nearby supernovae. If the neutrino pulse still arrives ahead at around the same amount of time as the nearby supernova, we can severely constrain any difference in speed between photons and neutrinos.

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    The supernova is 9.3 billion light years away. The current crop of neutrino detectors are not expected to be able to detect supernovae beyond a few hundred kiloparsecs. As things stand we need our detection range to improve by a factor of 10,000 before we could observe this.

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    Recall that this is a lensed event. The lens is 5 billion light years away.Without the lens we might not have spotted the supernova. Yet we see its photons from 9.3 billion ly away due to lensing and gravity focus. Type Ia events are also bright in neutrinos. Is there some evidence that neutrinos are not also lensed? A lens can increase intensity. Without lensing, intensity falls off as inverse squared where your statement would hold.

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    Lensing magnification rarely exceeds a factor of 10. Ergo the detection of the neutrinos from this event is still well outside our capabilities.

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    So, according to your numbers, lemsed events need to be within a few Mega parsecs to be detectable. This would allow monitoring the Local Group rather than just our galaxy for lensed supernovae.

    Another smoking gun possibility

    When Advance LIGO-VIRGO arrive online with completed ICECUBE and ANTARES, simultaneous arrival of multimessesnger signals would argue that neutrinos move at light speed. GWs, like neutrinos are not impeded or “choked” or “cloaked” or slowed like electromagnetic waves. So if they both move at light speed they will be detected together. Slow massive neutrinos would arrive later. So far, because GWs have yet to be detected at high sigma, there is nothing to report.
    However a study has been done with regard to multimessengers:

    Multimessenger Search for Sources of Gravitational Waves and High-Energy Neutrinos: Results for Initial LIGO-Virgo and IceCube

    http://arxiv.org/abs/1407.1042

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