Discovering the Elusive Positron g-Factor: A Comparison with CODATA's Best Value

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Discussion Overview

The discussion revolves around the value of the positron g-factor, particularly in comparison to the electron g-factor as presented by CODATA. Participants explore theoretical and experimental perspectives on the g-factor, its implications in the context of the Standard Model, and the significance of potential differences between the magnetic moments of electrons and positrons.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant notes difficulty in finding the explicit value of the positron g-factor, contrasting it with the readily available electron g-factor from CODATA.
  • Another participant mentions that the Particle Data Group (PDG) has experimental results showing no difference between the g-factors of electrons and positrons, citing CPT symmetry as a reason for their expected equality.
  • A participant expresses frustration over the lack of explicit values and provides a numerical value for the g-factor in a technical response, although the context of this value is not fully clarified.
  • Discussion includes references to the magnetic moments of protons and antiprotons, suggesting that experimental verification of differences is still relevant despite theoretical predictions.
  • One participant recounts a personal anecdote that sparked their curiosity about the g-factor, highlighting a conversation overheard regarding potential differences in magnetic moments, which they found implausible based on established physics.
  • Another participant asserts that the magnetic moments of electrons and positrons are known to be the same within a few parts per billion, attributing uncertainties to mass differences rather than the g-factor itself.

Areas of Agreement / Disagreement

Participants generally agree on the theoretical expectation that the g-factors of electrons and positrons should be the same, as dictated by CPT symmetry. However, there is an ongoing exploration of the explicit value of the positron g-factor and the implications of experimental results, indicating that some uncertainty and curiosity remain.

Contextual Notes

The discussion reflects limitations in the availability of explicit values for the positron g-factor and the reliance on theoretical frameworks and experimental data. The conversation also highlights the potential for misunderstandings in technical discussions about magnetic moments.

quiet
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.
 
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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.
 
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Thank You very much mfb. One more thing, if possible. What is the explicit value, which in CODATA does not appear?
 
quite said:
What is the explicit value, which in CODATA does not appear?

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.
 
The PDG, tables give the experimental values
Mu(proton)=2.7928473508(±85),
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.
 
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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.
 
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.
 
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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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