neutrino

Discussion in 'Physics & Math' started by granpa, Jan 1, 2015.

  1. granpa Registered Senior Member

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    The neutron is a subatomic particle with no net electric charge and a mass slightly larger than that of a proton.
    Outside the nucleus, free neutrons are unstable and have a half-life of 611.0±1.0 s (about 10 minutes, 11 seconds).
    A neutron spontaneously breaks down into a proton, an electron, and an electron-antineutrino.

    The radius of an electron in the ground state of a hydrogen atom is known as the Bohr radius and is equal to 0.529 angstroms.
    This is tens of thousands of times larger than the nucleus.
    It is often said, therefore, that the electron is too big to fit inside a neutron.

    But that is only true if the only force binding the electron inside the neutron is electromagnetism.
    If a much stronger force were attracting it then it would indeed fit inside the neutron.
    The only force strong enough to do that is the strong nuclear force.

    Unlike all the other forces the strong_force actually increases with (and is proportional to) distance from the center.
    (All other forces decrease rapidly with distance)
    Gamma rays emitted from nuclei typically have energies up to around 10 million electron volts.
    (2.4 × 10^21 Hz)

    Neutrinos have only one millionth of the mass of an electron yet they have the same amount of angular momentum. This suggests that they might be rotating fast enough to produce a very powerful and energetic gravito-magnetic field.

    Strangely, particles with gravito-magnetic fields would spontaneously align opposite to one another thereby canceling out each other's fields.
    (Exactly the opposite of what particles with magnetic fields do)

    Might this not explain some of the counterintuitive quantum mechanical behaviors that are seen in atoms?
    https://en.wikipedia.org/wiki/Electron_pair
    https://en.m.wikipedia.org/wiki/Cooper_pair

    Just as a neutron can be thought of as a spinning proton plus a spinning electron (albeit a surprisingly small one) with no net electric field yet still having a net magnetic field so a neutrino would consist of a spinning negative gravitational charge and a spinning positive gravitational charge with no net gravitational charge yet still having a net gravito-magnetic field. If so then there should be quite a strong gravitational field within the neutrino.
    Perhaps this is the source of the van der Waals force

    Gravito-electromagnetism is fascinating but the analogy with electromagnetism does break down in one crucial aspect.
    The gravitational field is not so much a field of "force" as it is a field of "acceleration".
    Everything within that field accelerates at the same rate regardless of its inertial or active gravitational mass.

    neutron = proton+electron+neutrino
    Neutino = positive active gravitational mass + negative active gravitational mass + ?
    if we could split the neutrino into its constituent parts then maybe we could use those to create an anti-gravitational effect.
    (And possibly a propulsion system too)
    (It might not be necessary to completely separate the two parts. A simple dipole field might be sufficient)
    Perhaps tau neutrino = electron neutrino + muon neutrino
     
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  3. origin Heading towards oblivion Valued Senior Member

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    I am going to have to stop you right there. The .529 angstrom radius is the most probable distance of the electron from the proton not the radius of the electron. So nobody is saying the electron is too big to "fit inside of a neutron".
     
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  5. OnlyMe Valued Senior Member

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    I would think that your last line above is a little backwards. Everything in a gravitational field accelerates at the same rate, because of its inertial/graviationnal mass. The equivalence of inertial and gravitational mass is critical to the observed equal accelerations. (BTW both inertial and gravitational mass are the same as rest mass. They are just identified separately for clarity of communication.)

    And.., gravitomagnetic and gravitoelectromagnetic are terms of analogy, for similarities between gravitation and electromagnetism or magnetic fields. I don't believe they were ever intended to represent complete descriptions of gravitation.
     
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  7. Farsight

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    3,492
    This is interesting stuff granpa. But I'm afraid I dislike the idea of "spinning negative gravitational charge and a spinning positive gravitational charge". Gravity is very weak, it's IMHO a total red herring. Gravitomagnestism is even weaker. Note that on brute properties, the neutrino is more like the photon than anything else. Have you got a washing line? Twang it to emulate a photon. Then get pair of pliers, and twist it and let go to emulate a neutrino.

    An electron doesn't have a radius in the conventional sense. But see atomic orbitals on wiki and note this: "The electrons do not orbit the nucleus in the sense of a planet orbiting the sun, but instead exist as standing waves." An electron is more like Saturn's rings, only even that doesn't do it justice. Its field is what it is.
     
  8. James R Just this guy, you know? Staff Member

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    39,397
    granpa,

    Yes, but it's important to realise that this doesn't mean that a neutron is made of a proton, an electron and a neutrino.

    The strong nuclear force doesn't act on electrons, which are leptons. It doesn't act on neutrinos, either.

    If you try a classical calculation of the size of something like an electron, and then calculate its rotational speed, it turns out that the electron needs to rotate faster than the speed of light. This suggests that the angular momentum of a fundamental particle such as an electron can't be interpreted in a classical way. It's analogous, but not the same as classical angular momentum.

    I thought the van de Waals force was fairly well understood already. Am I wrong?

    There's no evidence at all (yet) that a neutrino has any constituent parts. The same can be said for electrons.

    You may be interested to research neutrino oscillations. Things are rather more complicated than particle x is made up of particle y + particle z.
     
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  9. Farsight

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    3,492
    There's a non-sequitur here. You can see it in an old version of the Wikipedia Stern-Gerlach article:

    "Electrons are spin-1⁄2 particles. These have only two possible spin angular momentum values measured along any axis, +ħ/2 or −ħ/2. If this value arises as a result of the particles rotating the way a planet rotates, then the individual particles would have to be spinning impossibly fast. Even if the electron radius were as large as 2.8 fm (the classical electron radius), its surface would have to be rotating at 2.3×10^11 m/s. The speed of rotation at the surface would be in excess of the speed of light, 2.998×10^8 m/s, and is thus impossible.[2] Instead, the spin angular momentum is a purely quantum mechanical phenomenon."

    The non-sequitur is "it can't be rotating like a planet, so it can't be rotating at all". It just doesn't follow. Especially since an electron has a magnetic moment, and the Einstein-de Haas effect demonstrates that "spin angular momentum is indeed of the same nature as the angular momentum of rotating bodies as conceived in classical mechanics." It isn't rotating like a planet, it's rotating like a spin ½ particle. See Dirac's belt which mentions a Moebius strip which has a spin ½ feature. There's a major axis rotation AND a minor-axis rotation at half the rate. IMHO the AND might act as a multiplier.
     
  10. OnlyMe Valued Senior Member

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    3,914
    I almost responded earlier to that section of James' post, but my comment would have been out of context relative to the overall intent.

    The straightforward, responce is that the conclusion in James' comment, requires that inertia is operative relative to the angular momentum of fundamental particles.., like electrons and quarks... That is not settled science. In fact if as is suggested (theoretically) by Haisch et al, inertia is emergent from an interaction between the acceleration of charged fundamental particles and the EM spectrum of the ZPF, the angular momentum of a fundamental particle may not result in the same boundary conditions. The particle would not under those conditions be accelerating relative to or through the ZPF. In short there may be no inertial resistance to the angular momentum of a charged fundamental particle and thus there may be no speed of light limitation, in that specific case... And yes, my comment here is speculative and as a whole there are unresolved issues with that approach to inertia and gravitation, but the same might be true if they (Hairsch et al) were even close...

    Farsight's final conclusion that there can be no angular momentum associated with an electron, requires an addition of so many assumptions that it goes far beyond speculation and reads to me as a statement of belief, phrased as fact.

    What we are able to observe of reality, at both cosmological and quantum scales, tells us that angular momentum seems to be an inherent characteristic or component, where ever we are able to make discriminating observations and/or measurements, at either extreme! The angular momentum of an electron may or may not exceed the speed of light, but to say that classical experience is applicable, and thus excludes angular momentum completely, has not been proven to apply to the angular momentum of fundamental particles.
     
  11. Farsight

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    3,492
    What? How did you decide that that was my final conclusion? I didn't say that at all. Instead I said the Einstein-de Haas effect demonstrates that "spin angular momentum is indeed of the same nature as the angular momentum of rotating bodies as conceived in classical mechanics". There is angular momentum associated with an electron. The Einstein-de Haas effect proves it. What ought to sound like a statement of belief, is the notion that an electron doesn't spin like a planet and so doesn't spin at all. Of course it doesn't spin like a planet. if it did, it wouldn't be a spin ½ particle. See The discovery of the electron spin by S A Goudsmit and note this:

    "When the day came I had to tell Uhlenbeck about the Pauli principle - of course using my own quantum numbers - then he said to me: "But don't you see what this implies? It means that there is a fourth degree of freedom for the electron. It means that the electron has a spin, that it rotates".
     
  12. OnlyMe Valued Senior Member

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    3,914
    You're right. On re-reading that is not what you said.

    My confusion was partly because you seemed to be mixing, statements about spin as in angular momentum and spin as in quantum number. Not exactly the same things... And began with the non-sequitur statement, which appeared to link your comments directly to James' and the implications of FTL angular momentums.
     
  13. Farsight

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    3,492
    Thank you.
     
  14. James R Just this guy, you know? Staff Member

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    39,397
    What I wrote was this: "This suggests that the angular momentum of a fundamental particle such as an electron can't be interpreted in a classical way. It's analogous, but not the same as classical angular momentum."

    I'll say it again for emphasis: the electron doesn't rotate like a classical object.

    The Einstein-de Haas effect is very interesting, however, in that it shows that the quantum angular momentum of a collection of many particles scales up and behaves similarly to classical momentum in terms of conservation of total angular momentum in the absence of external torques and so on. This is one piece of evidence that shows that quantum angular momentum is analogous to classical angular momentum. Analogous, but not the same as.
     
  15. Farsight

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    3,492
    It doesn't show that quantum angular momentum is "analogous" to classical angular momentum. It shows that it's of the same nature. It means that the electron has a spin, that it rotates. It's fair enough to say the electron doesn't rotate like a classical object. It's fair enough to say the electron doesn't rotate like a planet. But I will reiterate: it isn't fair enough to say it doesn't rotate at all. That's the non-sequitur that's generally taught, and I'm afraid it's wrong.
     
  16. QuarkHead Remedial Math Student Valued Senior Member

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    1,740
    This is garbage. Electrons do NOT "spin" or rotate, they have rotational symmetry. You do not need to "spin" to have rotational symmetry. Which you would know if you ever studied the groups that describe continuous symmetries i.e. the Lie groups.

    Regarding the electron the Lie group of relevance is SU(2) that describes a symmetry of the form \(p= 4 \pi p\)
     
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  17. Dr_Toad It's green! Valued Senior Member

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    Does he italicize things he can't understand to make them seem important? What the hell?
     
  18. James R Just this guy, you know? Staff Member

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    39,397
    Farsight,

    I think we're splitting hairs, but it doesn't show that the electron rotates in any familiar (classical) manner. Given that an electron is, as far as we can tell, a point-like particle with no discernable size, it is difficult to even speculate about what it would mean for it to rotate.

    The fact is: nobody knows that it rotates in any conventional sense. To claim that it does it just a guess. The best we can say, based on actual data, is that it has a property that behaves a lot like classical angular momentum in some ways (in terms of conservation etc.), but quite differently in others (e.g. it is quantised in various ways).
     
  19. Farsight

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    3,492
    What you didn't appreciate is that It means that the electron has a spin, that it rotates is what Uhlenbeck said. It isn't garbage. The electrons does spin. If it didn't, it wouldn't move around "magnetic field lines", or towards and around a positron. Electrons and positrons move the way that they do not because of some action-at-a-distance magic, but because they're dynamical spinors.

    I know that they spin because I've studied electromagnetism. I've read all the old material. I know how it works. And that modern texts don't bring it out.

    It says nothing about the electron.

    It isn't pointlike, that's another modern-day myth. It's quantum field theory. Its field is what it is.

    I know it rotates in a conventional sense. If it didnlt, it wouldn't move the way that it does. It doesn't move linearly and/or rotationally because it's spitting out photons, or catching photons. That's yet another modern-day myth.
     
  20. Dr_Toad It's green! Valued Senior Member

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    Drunk already?
     
  21. PhysBang Valued Senior Member

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    Yes, we know that you have your own fantasy theory with absolutely no mathematics, no way to match observations and account for charge, and no way to make predictions. Do you have to poison every thread with your theories for which you can produce no observational evidence?
     
  22. QuarkHead Remedial Math Student Valued Senior Member

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    A telling remark, don't you all think? This majestic fool thinks science has not moved on in almost 100 years!

    Yes, and excluding the gravitational fields, these can be quantized - hence QFT.

    Yes, "modern day" as in the 1920's and 1930's, when the work of de Broglie and Born showed us that the electron can a) be characterized either as a wave or a particle depending on the method used to detect it,- or if you prefer, all elementary particles have an associated wave function - and b) that the square of the wave function is precisely the probability distribution for the position of the particle.

    Following these "modern" insights, it became meaningless to talk about electrons orbiting atomic nuclei, or even moving at all in the classical sense.

    Oh but I forgot- science stopped advancing 100 years ago, and living professionals have been fraudulently trousering tax-payer's money ever since. Farsight was wise - morally-minded even - not to embark upon an education that might have led to a career based upon such a scam
     
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  23. Farsight

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    In some respects it's moved backwards. In some respects it's now cargo-cult science. We have some nonsense myths nowadays, like the notion that electrons and protons throw photons at one another. As if hydrogen atoms twinkle, and magnets shine.

    Quite. It's quantum field theory. Not quantum point-particle theory. And yet the myth that the electron is a point-particle persists. Even though there's no experimental evidence to support this. None. All there is, is another silly non-sequitur. I suppose I ought to mention I had a little conversation about this on Tommaso Dorigo's blog. Some guy called KJ said every experiment of which I am aware is consistent with the electron being pointlike. I soon knocked that one on the head.

    That's point-particle thinking. That's wrong thinking. Have a read of weak-measurement work by Jeff Lundeen et al. See this: "So what does this mean? We hope that the scientific community can now improve upon the Copenhagen Interpretation, and redefine the wavefunction so that it is no longer just a mathematical tool, but rather something that can be directly measured in the laboratory.".

    Wrong again! Think about electron-positron pair production. Does the photon energy stop dead in no time flat? How about electron-positron annihilation. Does the photon energy accelerate instantly to c from a standing start? And how about magnetic moment? Is that magic too?

    Er no, because I've read a lot of new material too. Like the weak measurement stuff. Also see Aephraim Steinberg et al about that. You must know that I have my ear to the ground when it comes to physics research?
     

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