Talk:Nucleon magnetic moment

Merging proton and neutron magnetic moment articles, losing good article status for latter

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)

GA Review

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

---

This review is transcluded from Talk:Nucleon magnetic moment/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Hawkeye7 (talk · contribs) 02:58, 9 December 2022 (UTC)

Picking this one up. Review to follow in due course. Hawkeye7 (discuss) 02:58, 9 December 2022 (UTC)

The main problem with the article is a deficit of citations. Everything needs to be covered. So citations required:

• Description: first and third paragraphs

- Citations added; with a correction, see below. Bdushaw (talk) 17:18, 11 December 2022 (UTC)

• Neutron: first paragraph

- A bit of reorganization and citation work; done! The first couple of sentences introduce the section. Bdushaw (talk) 19:23, 11 December 2022 (UTC)

• Unexpected consequences: first paragraph

- Done!Bdushaw (talk) 19:07, 12 December 2022 (UTC)

• Nucleon gyromagnetic ratios: last paragraph

- Done!Bdushaw (talk) 19:07, 12 December 2022 (UTC)

• Proton nuclear magnetic resonance: first paragraph

- Citation added, with some cleanup.Bdushaw (talk) 19:07, 12 December 2022 (UTC)

• Determination of neutron spin: first paragraph

- Done! Mostly a rearrangement of existing cits. Bdushaw (talk) 19:11, 12 December 2022 (UTC)

• Control of neutron beams by magnetism: first paragraph

- Done! (not easy...statements of basic stuff that "everyone knows" are hard to cite!) Bdushaw (talk) 22:14, 14 December 2022 (UTC)

• Anomalous magnetic moments and meson physics: first paragraph

- Done! Bdushaw (talk) 22:18, 14 December 2022 (UTC)

• Quark model of nucleon magnetic moments: first and third paragraphs

- Done! All that material was from the Perkins cite; an undergraduate high energy physics textbook. Bdushaw (talk) 22:23, 14 December 2022 (UTC)

Measurement:

• You don't say why the neutron having a magnetic moment was "unexpected"

- Not exactly true since this was explicitly described in a section above, however it is a good catch that is worth clarifying. The change motivated a reorganization of the section. Bdushaw (talk) 11:16, 10 December 2022 (UTC)

• I would prefer that the article told us what university they were working at, rather than what city.

- Universities are better, to be sure. Done! Bdushaw (talk) 18:52, 11 December 2022 (UTC)

• "wave function" is two words

- fixed.

Duplicate links:

• Larmor frequency, Nuclear magnetic resonance, magnetic fields, Robert Bacher, Abraham Pais, quantum mechanical. Also: why is Bacher "R. Bacher" and "Robert Bacher"?

- Re:R. Bacher/Robert Bacher - all names of the article have been standardized to "First Initial. Last Name", name links corrected Bdushaw (talk) 10:18, 10 December 2022 (UTC)

- Question: I think you mean Larmor precession, which is the link, rather than frequency. The article has the initial link to Larmor precession, then indicates this as a Main article in the subsection of that name, then links "Larmor frequency" to that link. These don't seem redundant to me; they seem useful to the reader. Advice? Thx Bdushaw (talk) 10:18, 10 December 2022 (UTC) To some extent the issue occurs because "Nucleon gyromagnetic ratios" appears before "Larmor precession" in the article. I may move the gyromagnetic ratio section to the bottom, but somehow think it is better for the physical constants to be given near the top of the article. I'll think about it. Bdushaw (talk) 11:19, 10 December 2022 (UTC)

- Redundant links removed; still contemplating Larmor precession. Bdushaw (talk) 12:22, 10 December 2022 (UTC)

See also:

Not convinced that all of these are useful. Bohr magneton, electron magnetic moment, neutron diffraction, antineuton and antiproton are already linked in the article. (MOS:NOTSEEALSO: As a general rule, the "See also" section should not repeat links that appear in the article's body.) GAs have to conform to MOS:LAYOUT (Criterion 1b)

- Duplicate links removed.

References:

• fn 1, 2, 4, 5, 13, 27, 32, 40, 57 have a different date format from the rest. Suggest converting to dmy. (You should be able to do this by adding a {{use dmy dates}} template.)

- Ah, fixed now...mdy formatting, just so. Going with mdy format for the article. Bdushaw (talk) 12:39, 10 December 2022 (UTC)

• fn 28, 31: add access dates. Also: Why is NIST italicised here?

- access dates added. NIST italicised seems to be from the "web" reference format. NIST is not explicitly italicized. Bdushaw (talk) 12:04, 10 December 2022 (UTC)

• fn 35 isbn? page number? Also: why is 1991 in bold?

- Fixed and updated.

Hawkeye7 (discuss) 23:45, 9 December 2022 (UTC)

Thanks for the review! Alas, I am away from all my books and papers for the next several months, but I'll do what I can by way of citations. Bdushaw (talk) 10:07, 10 December 2022 (UTC)

There's no rush. Hawkeye7 (discuss) 10:17, 10 December 2022 (UTC)

I've made a first pass through everything, with corrections, deletions, citations, etc. as best as I can. I'd still prefer to keep the slightly redundant Larmor procession/frequency links (i.e., would a reader know to go to the Larmor procession article when they run across "Larmor frequency"? Seems a bit much to ask of readers.) Happy to try to make additional improvements as needed! Bdushaw (talk) 22:27, 14 December 2022 (UTC)

That's fine. But we still have some paragraphs lacking references:

• Second paragraph of "Description"
• First paragraph of "Neutron"
• First paragraph of "Unexpected consequences"

Hawkeye7 (discuss) 22:35, 14 December 2022 (UTC)

All fixed now, I hope. In the same spirit, I found a couple of other places where there were citation gaps, all fixed! Bdushaw (talk) 10:32, 16 December 2022 (UTC)

Final sentence of "Anomalous magnetic moments and meson physics" and we're good. Hawkeye7 (discuss) 10:50, 16 December 2022 (UTC)

That one is the famous Pais, "Inward Bound" reference, a marvel. Done! Bdushaw (talk) 12:25, 16 December 2022 (UTC)

GA review – see WP:WIAGA for criteria

1. Is it well written?

   A. The prose is clear and concise, and the spelling and grammar are correct:

   B. It complies with the manual of style guidelines for lead sections, layout, words to watch, fiction, and list incorporation:

2. Is it verifiable with no original research?

   A. It contains a list of all references (sources of information), presented in accordance with the layout style guideline:

   B. All in-line citations are from reliable sources, including those for direct quotations, statistics, published opinion, counter-intuitive or controversial statements that are challenged or likely to be challenged, and contentious material relating to living persons—science-based articles should follow the scientific citation guidelines:

   C. It contains no original research:

   D. It contains no copyright violations nor plagiarism:

3. Is it broad in its coverage?

   A. It addresses the main aspects of the topic:

   B. It stays focused on the topic without going into unnecessary detail (see summary style):

4. Is it neutral?

   It represents viewpoints fairly and without editorial bias, giving due weight to each:

5. Is it stable?

   It does not change significantly from day to day because of an ongoing edit war or content dispute:

6. Is it illustrated, if possible, by images?

   A. Images are tagged with their copyright status, and valid non-free use rationales are provided for non-free content:

   B. Images are relevant to the topic, and have suitable captions:

7. Overall:

   Pass or Fail:

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

"Seven orders of magnitude"

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)

A rainy day project: The contribution of the pion cloud

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)

Did you know nomination

The following is an archived discussion of the DYK nomination of the article below. Please do not modify this page. Subsequent comments should be made on the appropriate discussion page (such as this nomination's talk page, the article's talk page or Wikipedia talk:Did you know), unless there is consensus to re-open the discussion at this page. No further edits should be made to this page.

The result was: promoted by Theleekycauldron (talk) 10:00, 30 December 2022 (UTC)

(

• Comment or view
• Article history

)

• ... that the neutron, a subatomic particle, has no charge and yet has a magnetic moment? And that property indicates it is composed of quarks? Source: Vonsovsky, Sergei (1975). Magnetism of Elementary Particles. Moscow: Mir Publishers. Pages 73-74, 188
  https://archive.org/details/MagnetismOfElementaryParticles/page/n189/mode/2up?view=theater
  • Reviewed:

Created by Bdushaw (talk). Self-nominated at 00:16, 17 December 2022 (UTC).

•  Reviewing... Onegreatjoke (talk) 01:13, 17 December 2022 (UTC)
• @Bdushaw: Everything is good. However, your one hook has two hooks in it which isn't allowed. Either you find a way to connect the two or you get rid of the second hook. Also I linked neutron in the hook to better understand it. Onegreatjoke (talk) 15:13, 17 December 2022 (UTC)
• How about: "... that the neutron, a subatomic particle composed of quarks, has no electric charge and yet it has a magnetic moment?" Personally, I am fascinated by the fact that the magnetic moment was a red flag that the neutron was composite, but perhaps that's a bit much for an average reader. Bdushaw (talk) 16:34, 17 December 2022 (UTC)

yeah that's fine. Onegreatjoke (talk) 18:18, 17 December 2022 (UTC)