Tamburini: Neutrinos Are Majorana Particles, Relativity Is OK
    By Tommaso Dorigo | October 10th 2011 07:25 AM | 37 comments | Print | E-mail | Track Comments
    About Tommaso

    I am an experimental particle physicist working with the CMS experiment at CERN. In my spare time I play chess, abuse the piano, and aim my dobson...

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    Fabrizio Tamburini (left) is an old friend - I have known him since 1976, when we both used to attend the gatherings of the newborn Associazione Astrofili Veneziani, at the Lido of Venice. The love for astronomy had brought us together, but we took different paths in our scientific activities. Fabrizio remained maybe more faithful to his old love for the universe, and is now a well-known and respected astrophysicist, who studies original ideas in the physics of photon propagation and more. I repeatedly invited him to write about his research here, but so far he has not accepted, mainly for lack of time... But I am sure he will soon. In the meantime, he will be talking at TEDx Bologna on October 15th on his theory of photon vortices. Anyway, back to neutrinos.

    The recent result by Opera which hints at a possible superluminal motion of neutrinos produced by CERN and shot underground to the Gran Sasso mine in central Italy raised Tamburini's interest. Together with Marco Laveder, a colleague of the Physics Department of Padova University, Tamburini recently wrote  an interesting paper where he explains that Einstein's Relativity Theory needs not be put in discussion by the measurement: rather, the fact that neutrinos could exhibit an apparent superluminal motion is inherent in the theory written as far back as 1932 by Ettore Majorana, the talented and mysterious Italian physicist who disappeared shortly thereafter -probably to live in South America under false identity.

    Tamburini and Laveder's paper (which you can download from the arxiv) explains how a fictitious "imaginary mass" term in the solution of Majorana equations for neutrino propagation may be responsible for the observed faster-than-light travel of neutrinos in a dense medium.

    Specifically, the authors start from the hypothesis that the observed superluminal speed of neutrinos may be caused by matter effects, and they work out the effective imaginary mass which corresponds to each of the experimental measurements.

    What I find interesting is that Tamburini and Laveder do not stop at discussing the theoretical interpretation of the alleged superluminal motion, but put their hypothesis to the test by comparing known measurements of neutrino velocity on a graph, where the imaginary mass is computed from the momentum of neutrinos and the distance traveled in a dense medium. The data show a very linear behaviour, which may constitute an explanation of the Opera effect:


    This can't be right. Lorentz invariance is a purely geometric effect - there's no interaction term in a Lagrangian that can make a particle propagate superluminally, and the "fictitious" imaginary mass is an effective field theory approximation to some underlying interaction.

    You have to get rid of Lorentz invariance to explain this result. Otherwise you get CTCs and grandfather paradoxes.

    That would imply a remarkably strong coupling between neutrinos and matter. Neutrinos have a 10^-10 chance to interact with matter directly over the distance of 700 km, but their propagation speed is somehow changed by a factor of 10^-5?

    Well, Nameless, while I share your intuition, let's admit that there are holes in your argument and it's far from waterproof. Light isn't basically absorbed in glass either - but it's still slower by 1/3 than it is in the vacuum.

    Vladimir Kalitvianski
    Light is not absorbed in the glass in the sense of absence of dissipation but light in the glass is different - it is a collective motion mode so the coupling of the incident light to the glass is 100%.
    Vladimir, the quantities expressing numerical values of couplings may have various units but "percent" is not among them. Moreover, light works in the same way when it's diluted down to individual photons in which case it's completely analogous to individual neutrinos so your "collective" comments have nothing to do with the actual physics, either. Return to the asylum, please.

    Vladimir Kalitvianski
    Yes, I can express coupling in "percent". For example, if the glass thickness is smaller than necessary for 100% coupling, there will be incomplete refraction, you did not know that?

    Also, these collective phenomena with light in the glass are well "linear" or photon-number independent, to you information. What is valid for one photon, is valid for a beam. Only very high intensity light may cause non-linear effects which are also collective. In other words, photon in the glass is a quasi-particle, like phonon, plasmon, magnon, etc.

    I did not get you phrase about asylum. What do you mean with it?
    > light works in the same way when it's diluted down to individual photons

    I must be in a bad mood today, but holy cow. "diluted down" ... how can people do physics when they don't even have a way to express the situation whereby the photon field only has enough energy to yield a single photon?

    I don't think that you're in a bad mood today. I think that your brain is in a very bad shape in this particular life of yours. I have described the situation very crisply: the electromagnetic waves may be diluted down to very low energy densities so that the photons are propagating one-by-one. When it's so, their mutual interactions (and therefore also their statistics) are negligible and their behavior is dictated by the wave equation describing individual particles which is fully analogous to the equation describing the neutrinos. The photon-photon interactions are actually negligible even if the energy density is high.
    If you're not capable of understanding these simple ideas, please realize that the problem is on your side and this problem gives you no right to contaminate the public spaces with your utter stupidity.
    Vladimir Kalitvianski
    "The photon-photon interactions are actually negligible even if the energy density is high."

    We all know that, it goes without saying and you should not have written your "diluted" passage. Tell us about my 100% coupling and asylum instead.
    Looks like my second comment has disappeared AGAIN, so here's the condensed version of the idea.

    Consider a glass prism. When you shoot a photon at the prism, it comes out at an angle to the incident direction. Therefore, even if it's not absorbed, it still interacts with glass. Because glass really couples quite strongly with the EM field. And that is a prerequisite to being able to refract light.

    I know that my argument is not waterproof, but it still compares quite positively to Tamburini's argument, which is basically one big hole. :)

    Hmm have no idea why it disappeared - sorry about that.
    Hi Nameless,

    MSW effects which alter the neutrino oscillation pattern do so via virtual effects, so there needs not be a real interaction.

    Vladimir Kalitvianski
    Ah, virtual effects! They are virtual for what reason? Unexplainable or with no effect? If an effect is observable, it is a real effect.

    Generally I would like to learn the experimentalist's point of view on virtual particles one day.
    How is the Tamburini model reconciled with the Cohen-Glashow paper at arXiv 1109.6562 based on “… pair bremsstrahllung …[which]… proceeds through the neutral current interaction …" ?

    Is there some way in which a Tamburini superluminal neutrino avoids emitting neutral current pair bremsstrhllung and the consequent loss of energy going from CERN to Gran Sasso?


    Hi Tony,

    I will turn this question to Fabrizio. But I see no reason why bremsstrahlung should affect more the superluminal component.

    Tommaso, you say that you "see no reason why bremsstrahlung should affect more the superluminal component".

    Cohen and Glashow in arXiv 1109.6562 say "... in all cases of superluminal propagation, certain otherwise forbidden processes are kinematically permitted, even in vacuum ...".

    I do not see a detailed discussion or reference about that quote from their paper
    it may be relevant that they do say:
    "... The threshold energy for ... pair bremsstrahllung ... is ...
    2 m_e / sqrt( v_nu^2 - v_e^2 )
    where v_e is the maximal attainable velocity of an electron and m_e its mass ...
    we know that v_e = 1 [the speed of light] to a precision of at least 10^(-15) ...".

    Maybe Cohen and Glashow are saying that since the electron cannot go faster than light,
    neither can the neutrino unless it begins to emit bremsstrahllung electron-positron pairs.


    Ok, I understand... I hope Fabrizio pitches in then.
    Lorenz Invariance is already broken when the neutrino is traveling through a medium, the medium is a preferred frame.
    The paper however doesn't give any reason why mass term is created in a neutrino traveling through matter.

    >the medium is a preferred frame

    What the hell?

    All these Italians with their faster-than-light neutrinos... nothing more than a big ploy to direct attention away from the economic state of affairs in Italy...

    My question is exactly the same as Tony's. I don't see anything that would avoid the energy loss of known electroweak processes (e+ e- emission), something which was not seen in the OPERA final state mean energy distributions?!

    Can this "imaginary mass" term somehow effect the *real* kinematics of the neutrinos?

    In my own opinion you may not agree with me , so their we go.
    Breaking the speed of light is really a not pleasent news and is more like a big mistake that an actual discovery, Why. 
    1. Speed of ligth on the case of navigation pourpuse is totaly worthless effort, because it used on a real navigation may not only alters the magnetic fields on space causing a distress on it and may change it structure not for future discovery if not for future distruction of ballance. because it will affect only one side of it.
    2. to control for example a traveling device at that speed will be very dificult because the universe change every milliseond and what do you see if not what is there.
    3. and mos important, Knowing the way we do test and challenge nature today i can,t imagine what may be the result of something that we cant control outside of a laboratory.

    So my point is instead o forsing the speed of ligth why not follow it in using natural magnetic fields.

    Ill bet this sports for wining novel prices will end on a problem that we may not be able to fix.
    like we always do.

    If these neutrinos are travelling at superluminal speed, should they not be travelling backwards through time?

    If they are travelling backwards through time, how can someone travelling forwards through time observe them for more than an infinitesimally short period of time?

    >If these neutrinos are travelling at superluminal speed, should they not be travelling backwards through time?

    Only in some reference frames moving relative to the one in which the neutrino's superspeed™ is being measured. Yes that yields trouble, as they will arrive before being sent, so it will look as if the receiver end influences the sender end. Nobody wants that.

    Vladimir Kalitvianski
    Refractive index if "formed" as a result of collective effects. Remember slow neutrons that can be reflected from some media. It is also a collective interaction effect. Fast neutrons do not manifest that because of too short de Broglie wave length.

    The wave length of those energetic neutrinos is so short that it cannot result in collective effects.
    May be I produced some pure nonsense, but I tried to write the Dirac equation and the Majorana equation as pure quaternionic equations, rather than as complex equations that use matrices and spinors. The matrices and spinors immitate the behavior of quaternions and the sign selections that occur in quaternionic (skew) fields due to their conjugation and handedness.

    The quaternionic Dirac equation runs: (ψ ⇒ψ*)
      ∇ψ = m ψ*

    (No spinors, no α, β, or γ matrices, just quaternions!)
    ψ consists of a one dimensional real part and a 3D imaginary part. Here the star means conjugation. It changes the sign of all imaginary base vectors of the quaternion.  This action switches the handedness of the field. ψ* is the antiparticle of ψ.
    The covariant derivative D delivers

      = m ψ* + A ψ

    A derived equation is

      ∇(ψ ψ) = m (ψ ψ*) = 2 m|ψ|²

    Another derived equation is

      ∇(ψ ψ*) = 2 m Re(ψ ψ)

    With the interpretation of   (ψ ψ*) as a presence density follows:

      ∫˯ (ψ ψ*) dV=1

    and as a consequence 

      ∫˯∇(ψ ψ) dV =2m


    The quaternionic Majorana equation runs: (ψ ⇒ ψˤ)

      ∇ψ = m ψˤ

    In ψˤ two of the imaginary base vectors switch sign. This action DOES NOT switch the handedness. (ψ ψˤ) can no longer be interpreted as presence density. It is not even real!
    ∫˯ (ψ ψˤ) dV is not equal to one. It is not even real. So the factor m in the Majorana equation may be quaternionic rather than real.

    For more details see: .
    If you think, think twice
    Hans, if you've made an equation where the probablities don't sum to one, you've made an equation that can't describe any quantum particle. And its not suprising that the Majorana equation would not work with quaternions, it normally made with a two component weyl spinor, half as many components as a Dirac particle.

    The integral over the probability density is still one:
    ∫˯ (ψ ψ*) dV=1
    ∫˯ (ψ ψˤ) dV is not equal to one.

    If you think, think twice
    I adapted the article such that it contains an equation of (free) motion for each elementary particle of the standard model. With each equation of motion comes an extra equation that enables the computation of the coupling factor (=rest mass) of the particle. If this is true, then there is no need for a Higgs field.
    If you think, think twice
    There is gap between, "Proton Collision ->Decay to Muons and Muon Neutrinos ->Tau Neutrino ->[gap] tau lepton may travel some tens of microns before decaying back into neutrino and charged tracks." Use the case of Relativistic Muons?


    Superluminal neutrinos is correct.

    Is an effect of the existence of 3 basic lengths at the quantum level.

    The neutrino breaking the CPT violation, with a nonzero angle theta13, is bounded breaks Lorentz invariance at the quantum level as they move along roads in extra dimensions whose length is less than that corresponding to particles that do not violate CPT

    Wouldn't it be cool if people going into extra dimensions and New Physics at the tip of a hat learned to correctly use punctuation marks, spelling, and the basic grammatical structure of English?

    Jesus Christ.

    Anon, if you refer to the comments above, I think your troll contribution is unwelcome here. Please remind yourself to look at a world map and figure out that English is not the only one, nor the most common language in the world. People may need to talk in English here and elsewhere to communicate, but that makes them no inferior to you. How many languages do you master (with correct punctuation) ? Should we continue it in English, o ci mettiamo a parlare in italiano ? H mhpws sta Ellhnika ?

    Get down that pedestal, you don't look any better there.
    Appreciated, Tommaso. You should force the visitors to communicate in Czech. By the way, I liked your visit to Malta:
    Nice one. I knew it - but it works better with Chinese (the pronunciation makes the thing more likely, especially the "R" in Fork).
    The video is not just about forking! But yes, the Asians' inability to distinguish L, R, and nothing is a source of immense communication troubles.
    Italian is fun and melodic but I still think that the degeneration of the way of speaking since the time of Romans has been enormous. ;-)
    "Only in some reference frames moving relative to the one in which the neutrino's superspeed™ is being measured"

    Because movement is relative, does this not mean that every frame of reference that is not the F of R of the neurino could be considered as moving relative to that of the neutrino.

    BTW, Tommaso, I applaud your comments about the use of English. I post on a forum or two and struggle with the science, I dread to think what it must be like trying to do that in another language. I have great admiration for those brave people who do.