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Neutron decay products: n → p + e + ν + DC-photon?

  1. Apr 20, 2006 #1
    This is one of those old-high school questions that never got answered (And the search mechanism here doesn't narrow on quotemarks)--

    A neutron decays to a proton, electron, antineutrino ... But the highspeed escaping electron is a charge moving relative to (away from) the proton opposite charge and produces a photon (in the general sense; γ-ray; not much in the visible range) ... a noncyclic DC-pulse photon ... but,--

    Do we have information on this DC-pulse-"photon"?

    It radiates symmetrically about the p-e axis so it's got a wave-only non-ray behavior ... but, it is energy-to-be-accounted radiating into space .... Do we have an account on this, DC-pulse γ-radiant "photon" from neutron decay?

    (And, What do high energy physicists call this "extra" energy,-- unmodeled zero point flux?)

    Ray.
     
    Last edited: Apr 20, 2006
  2. jcsd
  3. Apr 26, 2006 #2
    Yes, emission of photon during beta decay is topic of current research at National Institute of Standards and Technology--I suggest you email authors of this paper:
    http://nvl.nist.gov/pub/nistpubs/jres/110/4/j110-4fis.pdf#search='neutron%20decay%20photon'
     
  4. Apr 28, 2006 #3
    The paper opens with:

    "Beta decay of the neutron into a proton, electron, electron antineutrino is occasionally accompanied by the emission of a photon…..this rare branch of a fundamentally weak decay has never been observed".

    Presumably it is the photon that has not been observed. If it is not observed (in the form of an interaction?), how is it 'known to occassionally occur'? A result was expected by the close of 2005, has this been reported?

    I would not expect the antineutrino and the photon to occur in the same decay, only one or the other, hence my interest in this item.
     
  5. Apr 28, 2006 #4
    Why?

    You have to conserve lepton number- so the electron anti-neutrino has to show up, always. That is why it is an anti-neutrino. But it is the sharing of the available energy that allows the creation of the photon.

    I have not read the paper, but I assume they are finding some missing energy in some instances of the reaction, or it could be a momentum conservation issue also. That would be my guess- the same way the neutrino was hypothesized long before its experimental observation.
     
    Last edited: Apr 28, 2006
  6. Apr 30, 2006 #5
    Sorry, cannot say why as PF rules rightly prevent promotion of personal (i.e. unpublished) theories. But it is worth remembering a comment I read in one book. It said that as a rough guide "rules work even though not directly proven by experiment"; (for example, the allocation of fractional charge to quarks), "Laws are proven by experiment". New theories might get away with breaking the rules but would never get away with breaking the laws. I would be back to square one if both antineutrino and photon were proven to occur, (by experiment) in neutron decay.
    Perhaps someone can tell us the precise current state of this problem?
     
    Last edited: Apr 30, 2006
  7. Apr 30, 2006 #6

    ZapperZ

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    Since when? And what exactly are "directly proven by experiment"? Considering the tons of experiments that are consistent with these fractional charges, how much more convincing do you need?

    Sorry, but physics doesn't work this way. A theory doesn't "graduate" into a law. That never happens because the NAME is irrelevant. Physicists do not care much to the name attached to something. It is the CONTENT of that something that is more important. We call something a "theory", a "law", or a something simply to differentiate it from experimental aspect of the work. Nothing more, nothing less. This is what many creationists do not understand when they attack the "Theory" of evolution simply due to the word theory. Do not confuse this word with that used in ordinary conversations.

    And "proven" is a very dubious concept in physics, because that word has an association with mathematics. Nothing in physics is "proven" the same way it is done in mathematics. Experimental verifications only ADDS to the degree of certainty of any theoretical ideas. They don't prove it. The band structure theory of solids has an extremely high degree of certainty so much so that you are using it in your modern electronics.

    Zz.
     
  8. Apr 30, 2006 #7

    Astronuc

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    Actually, if one reads the text, it adds, "while it has been extensively investigate in more exotic systems," i.e. presumably nuclei. See reference 1.

    The investigators are looking at 'free' neutron decay for the photon emission. The effect has apparently not been observed in the beta decay of 'free' (isolated) neutrons.

    Ostensibly, it may have to do with the fact that the negatively charged beta particle moves in the Coulomb fields of several protons and is thus subject to a variable electric field. It may not necessarily produce a photon in the field of a proton. Just a thought.
     
  9. Apr 30, 2006 #8
    :confused: But, is there such a quantum entity as a "free" neutron [N] ? Is not [N] at minimum energy of 2.22 MeV bound to a proton to form stable deuteron [NP], or to another neutron to form unbound dineutron [NN]--(with about 0.067 MeV pair energy between the two neutrons--see Sofianos et al. 1997 J. Phys. G 1619-1629). Perhaps this suggests that the added photon energy during beta decay derives from the strong force, and is not a fundamental property of either neutron nor proton ?
    But, I have a question. Consider that helium-3 [PP,N], and helium-4 [PP,NN] are very stable--thus no beta-decay with or without added photon is predicted--yet we have several protons ? How does this mesh with your hypothesis ? In contrast, hydrogen-3 or triton [P,NN] and helium-6 isotope [PP,NNNN] are very unstable and show beta minus decay. I would be interested in knowing if either of these beta decay processes have been observed to yield the "added" photon of energy.
     
  10. May 2, 2006 #9
    Since when? And what exactly are "directly proven by experiment"? Considering the tons of experiments that are consistent with these fractional charges, how much more convincing do you need?

    Fractional charge values for quarks are allocated to make the combined charges total equal to the proton charge and therefore comply with the conservation of charge rule. The whole statement is part of an interpretation. It is possible to make an alternative interpretation that matches the experimental observations, but does not include a photon in this particular decay.

    Sorry, but physics doesn't work this way. A theory doesn't "graduate" into a law.

    Quite so, but that is not what I wrote, which is about the difference between rule and law, something quite different. That is why I queeried the expectation of a photon in the neutron decay mentioned in the original submission; I do not expect the photon to be found (different interpretation).
    Rade's submission is far more interesting in that it adds to the explanation of the problem and in doing so provides another avenue for exploration (one that also indicates that the photon will not be found).
     
  11. May 2, 2006 #10
    Rade

    Perhaps this suggests that the added photon energy during beta decay derives from the strong force, and is not a fundamental property of either neutron nor proton


    Please give an example of strong force without the presence of quarks.

    Surely SF particles emit neutrinos and leptons emit photons? (each class of particle/force has its own class of zero or near zero mass particle). Although it sometimes takes more than one interaction from decay start to decay stop?
     
    Last edited: May 2, 2006
  12. May 2, 2006 #11

    ZapperZ

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    Sorry, but as far as I know, there hasn't been any experimental evidence that such "allocations" are not consistent with any experimental observations. And if you look carefully, almost EVERY observations that deduces the charge of any object is based on such charge conservation laws. So this is not something unique that is solely done for the quarks. If you say that this is "indirect" measurement, then all of what you know about E&M are also "indirect".

    And no, we also cannot simply FORCE things to fit in if that isn't what nature is. Case in point: the "missing" angular momentum of protons that simply cannot be accounted for by the quark spins. Clearly, we simply cannot force the quarks to take up the spins when they don't have it! The experimental evidence won't be consistent! This is clearly a proof that we simply cannot assign stuff when they don't fit into what we observe experimentally. No such thing has ever been an issue with regards to the fractional charges.

    Where in physics is this ever an issue, or something that actually makes a difference?

    Zz.
     
  13. May 2, 2006 #12
    Where in physics is this ever an issue, or something that actually makes a difference?

    Sorry, but as far as I know, there hasn't been any experimental evidence that such "allocations" are not consistent with any experimental observations



    Being as precise as possible is essential to understanding. I was careful to note that the current ‘allocations’ agreed with experimental evidence before claiming that other 'allocations' might be possible.


    Clearly, we simply cannot force the quarks to take up the spins when they don't have it! The experimental evidence won't be consistent!

    I did a quick check on this and notice that while other writers also refer to experiments, Physical Review Letters are more precise, they refer to computer simulations; once again I think the difference is important to our understanding of what is being said. A computer simulation is an interpretation, not a proof; a group of consistent experimental results is a proof.
    The difference between what actually occurs and what is believed to occur is important in that it tells us where further progress can, or cannot, be made.

    Back to the opening submission, are there any other cases where a predicted particle fails to appear?
     
    Last edited: May 2, 2006
  14. May 3, 2006 #13

    ZapperZ

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    So you were making speculations without basis or physical evidence?


    Er.. come again? Do you think Zheng et al, PRL 92, 012004 (2004) is a "computer simulation"?

    Zz.
     
  15. May 3, 2006 #14
    Er.. come again? Do you think Zheng et al, PRL 92, 012004 (2004) is a "computer simulation"?

    No I refered to the paper quoted:
    see Sofianos et al. 1997 J. Phys. G 1619-1629).

    So you were making speculations without basis or physical evidence?

    No, I said the evidence was open to other interpretations. Clearly the fact that in current theory there is a missing photon problem shows that current rules might be subject to change (but, of course; this does not open to question, current laws).
     
  16. May 3, 2006 #15

    ZapperZ

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    Who cited that? I was illustrating that one simply cannot make bogus assignment simply for accounting sake without experimental verification. The fractional charges for quarks are WELL VERIFIED. I gave you an illustration where we simply cannot force quarks to have any value just so they obey some conservation rules that Nature doesn't give them, and the "missing" spin is one specific example. You somehow turned that around and said that that was nothing more than "computer simulations"?

    Show me where fractional charges assigned to the quarks do not fit experimental verifications. If there isn't, and you have an "alternative theory", then let's see it in the IR forum.

    Zz.
     
  17. May 4, 2006 #16
    What? Show me where there is a peer reviewed paper that makes this claim: "there is a missing photon problem."

    The original paper cited states that occassionally there might be (since it has not been observed) a photon emitted in this reaction.
     
  18. May 4, 2006 #17
    Show me where fractional charges assigned to the quarks do not fit experimental verifications.

    This is where the difference between rule and law is important. The rule is experimentally verified but the rule cannot beome a law until the charge of an individual quark can be proven to be that given by the rule. In other words the rule is mathematically correct but cannot be shown to be factually (or scientifically) correct.
    There is a fine line to be drawn here because the Standard Model does not have a complete interpretation, and it is vital therefore, that researchers understand the difference between mathematically proven and factually proven if there is to be any improvement in the interpretation (explanation in words).
    Relativity did not prove Newton to be wrong, it did offer an improvement of our understanding of how gravity works - different mathematics but almost the same result. I would expect any improvement in the interpretation of the Standard Model to be along the same lines.
    For example to his dying day Einstein hated his 'C squared' constant because its need cannot be explained. So if we could remove 'C squared' from any equation that uses it, that would be progress. We can change the mathematical rule, as long as the new equation fits the experimental observation, but this does not necessarily invalidate the old rule.
     
    Last edited: May 4, 2006
  19. May 4, 2006 #18

    ZapperZ

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    You seem to like to switch gears, and ignore points being made. Could you show me examples in physics where there is such a thing as a "rule" becoming and being called a "law" later on?

    Good grief!

    Zz.
     
  20. May 5, 2006 #19
    You seem to like to switch gears, and ignore points being made. Could you show me examples in physics where there is such a thing as a "rule" becoming and being called a "law" later on?

    I am quoting from memeory passages by Pais, Barut, Veltman and Baggot. Will try and find time to find references.

    then let's see it in the IR forum

    Done.
     
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