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Free neutrons are unstable: would a muon in say uranium be stable ?

  1. Sep 14, 2006 #1
    free neutrons are unstable: would a muon in say uranium be "stable"?

    free neutrons are unstable: would a muon in say uranium be "stable"?

    free neutrons decompose and have a half-life of about 15 minutes.
    neutrons bound in a nucleus, especially in a magic shell configuration like helium-4 or iron, have an indefinite lifespan.

    muons are unstable with 4.4 msec half-life.
    muon decay can be lengthen near-light speeds due to special relativity time dilation

    would a muon in an extremely heavy nucleous like uranium where 1S electrons have near-light speeds be stable, or have a long half-life?

    such muons might serve as a basis for cold fusion.

    remove 1 electron from a uranium atom (or other stable heavy isotope)

    replace with muon.
  2. jcsd
  3. Sep 14, 2006 #2


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    Muons are not stable, not even in an atom's 1S orbit, not even if the atom is uranium.
  4. Sep 15, 2006 #3
    Has it ever been tested or does theory rule it out a priori?
  5. Sep 19, 2006 #4
    You are acutally talking about two different kind of particle.

    The neutron gets to be stable into the nucleus, mainly because of the strong nuclear interaction.

    The muon, even into a 1S state, is mainly influence by the Coulomb force acting on it. That is one of the reasons why it does not become stable.
  6. Sep 19, 2006 #5
    You should check out the book by deBenedetti titled "Nuclear Interactions." There is a nice treatment of muonic atoms and weak interactions in nuclear physics contained within.

    The funny thing about the muon in a 1S orbit of a large nucleus like uranium is that the mean radius of the muon will be inside the nucleus. The way to see this is as follows: the muon is about 200 times more massive than the electron. The bohr radius is inversely proportional to the mass. So the muonic orbits have 1/200 the radius of the electronic orbits. So... do you think the muon will interact with the nucleons in the nucleus at some point?

    For your lighter nuclei, there has been experimental work done with the capture of muons. Do a google search on "muonic atoms" and you will turn up a lot of papers.
    Here is one that does a nice (but technical) overview of muon-electron transitions in muonic atoms: http://arxiv.org/abs/hep-ph/9801218" [Broken]

    Hope this helps,
    Last edited by a moderator: May 2, 2017
  7. Sep 19, 2006 #6

    Meir Achuz

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    The neutron in He is stable because the energy release in neutron beta decay is less than the energy difference between He^4 and 3 p and 1 n.
    The energy release in mu-->e decay is much greater than any nuclear energy differences, so mu's still decay when bound in a Coulomb orbit.
    The relativistic effect in a muonic atom is small because of the muons large mass.
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