# Talk:Nucleon magnetic moment

The proton magnetic moment article was mostly redundant with the neutron magnetic moment article, and those two topics are intimately related.  It made no sense (eventually) to have separate articles for the two.  So I have merged them (being bold, and noting a general apathy to my posts suggesting a merge).  However, the neutron magnetic article was rated a "Good Article", and the combined article can no longer claim that status, IMO.  The plan would be to let this article evolve/develop a bit more with the change, then request another review for Good Article status. Bdushaw (talk) 11:36, 1 October 2022 (UTC) Bdushaw (talk) 11:36, 1 October 2022 (UTC)

The Description section had a sentence that the magnetic forces were seven orders of magnitude smaller than the strong forces.  The Reviewer above requested a citation for this statement; support for such a statement is difficult, because the statement is so basic/introductory that it is hard to find an explicit statement supporting it.  I suspect one would need an undergraduate nuclear physics textbook; the two I had were not helpful, however.  The references I have just barrel on with ignoring the neutron's magnetic moment (apparently everyone is already aware the magnetic forces are inconsequential!). Anyways, it occurred to me the "seven orders of magnitude" was not correct - I think that originally came from the neutron article.  The point of it was that, at atomic dimensions, the Coulomb force was 7X weaker than the strong force, I believe.  In our case the neutron's magnetic moment is 3 orders of magnitude less than the electron's, so an estimate of ten orders of magnitude smaller is more likely correct.  I've gone with a generic "many orders of magnitude".  We could compute it directly, of course, though that would be Original Research. The Physics Today citation is pretty good for supporting the point, though not exactly. Bdushaw (talk) 17:30, 11 December 2022 (UTC)

I was wondering what happened to the general notion of the pion cloud - that theory, while not working to account for the magnetic moments, was likely not entirely wrong.  It turns out there are a number of recent papers that address the question of the contribution of the pion cloud as a correction to the magnetic moment computed from quarks, I believe.  This topic is out of my jurisdiction, and perhaps getting into OR.  Certainly more technical than I am willing to tackle.  Nevertheless, there it is.  One can see examples with a google search to pion cloud magnetic moment etc. Bdushaw (talk) 22:27, 10 May 2015 (UTC)

There was all this effort on the pion cloud approach that went on for decades, and then the quark explanation came about, causing the aforementioned pion work to be abandoned, it seems.  And yet, some quite smart people worked on the pion physical picture, and one cannot just abandon such theoretical work without determining either it was wrong (and where/how) or that it is equivalent to the quark theory.  One surmises that the recent QCD numerical work that models the magnetic moments very well, apparently, also accounts for the effects of the pion cloud around the nucleons.  As just mentioned, I can't comprehend a lot of this theoretical work, but reconciling the two views seems to me to be a small hole in physical understanding. Shankar's book on QM, 2nd edition, has a brief comment on the pion theory (a mess), without a mention of the quark view.  (I posted an inquiry to him directly (!), but he said he didn't know enough about the issue to comment.) Bdushaw (talk) 13:20, 13 December 2022 (UTC)