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B Positron g-factor

  1. Oct 12, 2017 #1
    Hi. I registered recently. Maybe you can help me with the following. I have sought the value of the electron g-factor and abundant information has appeared, including the best value exposed in CODATA.

    With the value of the positron g-factor I have not been lucky. Comparative approaches of theoretical type appear, but I can not find the explicit value.
  2. jcsd
  3. Oct 12, 2017 #2


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    PDG has experimental results, no difference between electrons and positrons has been found.

    CPT requires that electron and positron have exactly the same g-factor, therefore Standard Model predictions for the electron and the positron are the same.
  4. Oct 12, 2017 #3
    Thank You very much mfb. One more thing, if possible. What is the explicit value, which in CODATA does not appear?
  5. Oct 12, 2017 #4

    Vanadium 50

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    Seriously - you need us to type it in for you? You can't follow the link - or, alternatively, do the arithmetic - yourself?

    a (and g = 2(1+a)) is 1159652187.9(4.3 ) x 10^-12.
  6. Oct 13, 2017 #5


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    The PDG, tables give the experimental values
    Mu(antip) =−2.7928464(±23).
    This shows that, within experimental error, the antiproton has the same magnetic moment as the proton.
    You can convert these numbers to the g value using the definition of g.
    Whatever the standard model or PCT says, it is still important to look experimentally for any difference.
  7. Oct 13, 2017 #6
    Hi and thanks for all persons. I'll try to expose why I'm looking for explicit value on the internet, or wherever. I was traveling by train. Behind me two men held a technical conversation out loud and I could hear it. One of them, with a group, tried to use components of a positron tomograph for another purpose. He said that something was difficult and that, after exhausting other possibilities, there were two. One, an error in calculations made by the group, but they were simple calculations, revised several times and found no error. Another, that the magnetic moment of the electron and the magnetic moment of the positron differed a lot. But this second idea was absurd, since physics assures the equality of both magnetic moments. That made me curious. I started the search on the internet and after failing in the attempt, I raised the question here in the forum.
  8. Oct 13, 2017 #7


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    We know they are the same within a few parts per billion (and the uncertainty doesn't come from the g-factor, it comes from the masses). That is way more precise than everything they might need in applications.
  9. Oct 13, 2017 #8
    Yes, it was only a moment of curiosity. I will not try to look for more. I thank all the people who kindly approached this thread.
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