Talk:Proton

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Was there discussion on this? I suppose since gluons can interact with gluons the previous one wasn't right, but now they must interact that way. Is there something in between? Gah4 (talk) 20:54, 4 November 2020 (UTC)

I would like to see included (not necessarily in the intro) a simple explanation of the meaning of each diagram, followed by an explanation of which one is correct and why. I don't think this is obvious to most readers. Dirac66 (talk) 03:19, 5 November 2020 (UTC)

I probably thought that the old one was close enough for most people. That there are quarks, and they interact through gluons. For most people that is probably enough. But since gluons can interact with each other, it does make sense to indicate that. But the picture then looks like gluons only interact in a three-way interaction, which isn't true. I suppose I don't know gluon statistics well enough. As well as I know, two gluons can interact, such that two go in and two go out. Are there two in one out, or one in two out, interactions like the diagram? Gah4 (talk) 06:32, 5 November 2020 (UTC)

See Talk:Proton/Archive_1#diagram of quarks in proton. The diagram does not represent gluon flux tubes, but rather interactions between quarks and gluons in general. This is intentional, and adopted across the board on Wikipedia, see Neutron, Antiproton, Antineutron, Nucleon, etc. If you want to change this, get consensus at WT:PHYS first. 23:58, 5 November 2020 (UTC)

It seems that Talk:Proton/Archive_1#diagram of quarks in proton is a few years old. I started a discussion in WT:PHYS as there isn't one so far. I did find this as a start to QCD diagrams. Gah4 (talk) 00:50, 6 November 2020 (UTC)

see: c:Commons:GL/I#Representation_of_the_gluon_field_in_the_nucleons --Mrmw (talk) 11:54, 16 November 2020 (UTC)

This was discussed at length at Wikipedia talk:WikiProject Physics/Archive December 2020#quarks and gluons in diagrams and I thought there was a strong consensus that the Delta diagram was wrong and the Wye diagram was correct. So why does the article still show the Delta diagram? 67.198.37.16 (talk) 08:16, 14 February 2021 (UTC)

p.s. to reply to User:Dirac66 above, the discussion at WP:Physics included a derivation of the Wye diagram from "first principles", the QCD Lagrangian, and also explained what was wrong with the Delta diagram. Perhaps that explanation could be reworked into a form suitable for inclusion in this article. 67.198.37.16 (talk) 08:21, 14 February 2021 (UTC)

There is discussion about lone protons. I suspect that the reason this is a question at all is that chemists like to write H+ when they actually mean H3O+. If there are electrons around, and the temperature is not too high, it will grab one. High means plasma or, as noted, accelerators. Gah4 (talk) 14:26, 28 February 2021 (UTC)

In Proton § Quarks and the mass of a proton, it says "As noted, most of a proton's mass comes from the gluons that bind the current quarks together, rather than from the quarks themselves." As I understand it, the confinement of the quarks forces them to relativistic velocities, with the resultant kinetic energy contributing significantly to the hadron's mass. Should the quoted sentence not be amended accordingly? —Quondum 02:36, 4 June 2021 (UTC)

Quondum, there is a newer source nicely explaining all the contributions to the mass at https://physics.aps.org/articles./v11/118. StarryGrandma (talk) 23:12, 4 June 2021 (UTC)

Not found.—Anita5192 (talk) 23:24, 4 June 2021 (UTC)

The correct URL is https://physics.aps.org/articles/v11/118 without the period after the word articles. Computers are very picky sometimes. Dirac66 (talk) 00:26, 5 June 2021 (UTC)

Thanks, that is far more understandable, and largely in line with what I had understood. The term "binding energy" seemed to be so misused that it was just confusing. I edited this in. —Quondum 01:25, 5 June 2021 (UTC)

The NMR section strongly (too strongly) indicates that it couples to spin. It actually couples to the magnetic moment, which of course is related to spin, but not exactly spin. For example, neutrons are also spin 1/2, but have a different magnetic moment. Gah4 (talk) 10:55, 15 February 2022 (UTC)

What wording would you suggest for that section? Dirac66 (talk) 03:12, 18 February 2022 (UTC)

How about spin magnetic moment which seems to be real enough to have its own page. Gah4 (talk) 10:47, 22 August 2022 (UTC)

Good idea, so I have rewritten the paragraph around the term "spin magnetic moment". Perhaps you can improve it further. Dirac66 (talk) 20:58, 22 August 2022 (UTC)

Recently I have learned of some new research indicating potential for an additional quark in protons and so am bringing this up to see how it should be addressed.

https://www.nature.com/articles/s41586-022-04998-2

Perhaps this should be mentioned under "Quarks and the mass of a proton" as unconfirmed, but relevant research? Should we wait instead or do something else? StellarRemant (talk) 19:56, 17 August 2022 (UTC)

additional secondary source is available here. — Preceding unsigned comment added by 151.19.204.39 (talk) 00:30, 20 August 2022 (UTC)

That result is only 3 sigma, which means it is not discovery. 109.252.168.16 (talk) 17:43, 20 August 2022 (UTC)

I didn't actually read the article, but at some point you can always have virtual quark-antiquark pairs. How many depends on the energy available, and quark masses. Gah4 (talk) 10:46, 22 August 2022 (UTC)

The article currently states that Rutherford proposed the reaction "¹⁴N + α → ¹⁴C + α + H⁺" ("History" section, 5th paragraph). But this equation has different mass numbers on each side: 18 on the left and 19 on the right. Is this a typo? Or maybe an incorrect transcription of Rutherford's proposal into modern notation? Should it be ¹⁴N + α → ¹³C + α + H⁺? Indefatigable (talk) 17:05, 19 October 2022 (UTC)

Possibly a typo when entered. But I've removed it as failing verification. The source doesn't mention a proposed reaction, only that Rutherford thought charged hydrogen atoms were torn off from the bombarded nucleus, implying that atomic nuclei of lighter elements were made up of combinations of hydrogen and helium. StarryGrandma (talk) 19:22, 19 October 2022 (UTC)

The section on charge radius is confusing. The story to be told here is 1) the value and meaning and 2) recent history of the value due to changes in types of experiments. These bits are mixed up and the section tails off with some math. Johnjbarton (talk) 16:50, 27 March 2024 (UTC)

I suspect there is no good way to explain charge radius without some math. The proton contains quarks and gluons moving at high speed, according to their Fermi velocity. As usual for quantum problems, there is an exponential tail. With appropriate math, one can come up with a single number to describe the radius. Different math will give a different number. Gah4 (talk) 20:17, 27 March 2024 (UTC)

Sorry I don't agree. The proton radius value is clearly and unambiguously defined and used in different kinds of theories and experiments.

• Miller, Gerald A. (2019-03-07). "Defining the proton radius: A unified treatment". Physical Review C. 99 (3). doi:10.1103/PhysRevC.99.035202. ISSN 2469-9985.

The Proton radius puzzle page is actually pretty good on the charge radius story. I made a lot of changes to it, please review. Johnjbarton (talk) 01:39, 28 March 2024 (UTC)

Sorry, I didn't explain it well. Once you define the expression for the radius, then it is well defined. Consider the Gaussian. The width could be FWHM or FWTM, but once you say which one, it is well defined. Anything with an infinite tail, which is pretty much everything in quantum mechanics, needs a nice definition. But someone else could come along, and use a different one. If you don't know anything about the charge distribution, which might apply to some readers, then you have to explain it all the way back. That would be especially true for less mathematical readers. Reminds me, there used to be a joke about the page Chlorine-releasing compounds defining them as compounds that release chlorine. Seems to have changed now, though. Gah4 (talk) 19:47, 28 March 2024 (UTC)

Yes, common, non-physicist meaning of "radius" is ambiguous for elementary particles. It would be great if we could find a ref explaining how the official def can be "interpreted". The bad news is that the interpretations I have found point to 2D parton models because all of the interactions involved are relativistic. So a vaguely spherical fuzzy ball is not a thing here. Johnjbarton (talk) 19:58, 28 March 2024 (UTC)

To be more specific, what is f(r/Rp)? That is, the radial part of the charge density function? Since protons have spin, they are not spherically symmetric, so there could be other terms besides radial dependence. Gah4 (talk) 02:30, 29 March 2024 (UTC)

The shape is not determined experimentally. Johnjbarton (talk) 16:18, 29 March 2024 (UTC)

So you see the problem of giving an exact size for something of unknown shape. I suspect this isn't a problem for physicists, but many others will read the article. Some might assume a ball of uniform charge and given radius. But yes, once you assume a specific charge distibution function, then you can measure it accurately, within that assumption. Gah4 (talk) 18:26, 29 March 2024 (UTC)

Yes I agree with your overall point. I just don't know how to address it with refs. Johnjbarton (talk) 20:46, 29 March 2024 (UTC)

This article has details:

• Gao, H.; Vanderhaeghen, M. (2022-01-21). "The proton charge radius". Reviews of Modern Physics. 94 (1). doi:10.1103/RevModPhys.94.015002. ISSN 0034-6861.

For example, in discussing data for hadrons:

• • "the transverse density at equal light-front times can be interpreted as a two dimensional flash photograph of a three-dimensional object"

Johnjbarton (talk) 15:48, 3 April 2024 (UTC)

Wikipedia generally prefers secondary sources. In a recent edit I used the lifetime from the source

• S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024) and 2025 update. In particular the page https://pdg.lbl.gov/2025/listings/rpp2025-list-p.pdf

In my opinion this is the authoritative source for particle data. We editors of Wikipedia have no reason to use any other source for this data.

I propose to use the PDG value, mean_lifetime = > 0.96×10³⁰ years referencing S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024) and 2025 update. I ask you to Agree or Disagree or join discussion at Project physics.Johnjbarton (talk) 19:13, 21 August 2025 (UTC)

• Agree I see no argumental flaws here.--ReyHahn (talk) 19:44, 21 August 2025 (UTC)
• Agree – It should be made clear that these are experimentally determined rather than theoretical values; a footnote to this effect would be clarifying. In this instance, significantly improved results from a primary source can be mentioned in the footnote if sufficiently authoritative. —Quondum 20:01, 21 August 2025 (UTC)

GUT and SUSY give a proton lifetime lower limit of around 10³⁴ years — see the source.^[1] 217.76.14.212 (talk) 21:31, 22 August 2025 (UTC)

Listen, let’s end the debate and set the lifetime at 3.6 x 10²⁹ years. 217.76.12.178 (talk) 11:33, 23 August 2025 (UTC)

• PDG is authoritative here. Headbomb {t · c · p · b} 04:32, 26 August 2025 (UTC)

Millikan measured the Elementary charge and published in 1910. It was less accurately known earlier from measurements of the Faraday and Avogadro's constant. But the article indicates that Thompson measured it in 1898. Elementary charge doesn't mention that one. Particles moving through a magnetic field measure charge/mass, which is also what Thompson claims. Gah4 (talk) 00:00, 26 November 2025 (UTC)

Whittaker on page 407 says:

The magnitude of the electric charge on the ions of gases was not known with certainty until 1898, when a plan for determining it was successfully executed by J. J. Thomson.

I'll look into this some more. Johnjbarton (talk) 01:25, 26 November 2025 (UTC)

Ok I updated Elementary charge, please review. Johnjbarton (talk) 17:55, 30 November 2025 (UTC)

See Nature article: https://www.nature.com/articles/s41586-026-10124-3 published 11 Feb 2026 Quote from article abstract: "Here we present a measurement of the 2S–6P transition in atomic hydrogen with sufficient precision to distinguish between the discrepant values of rp and enable rigorous testing of QED and the SM overall. Our result ν2S–6P = 730,690,248,610.79(48) kHz gives a value of rp = 0.8406(15) fm at least 2.5-fold more precise than from other atomic hydrogen determinations and in excellent agreement with the muonic value. The SM prediction of the transition frequency (730,690,248,610.79(23) kHz) is in excellent agreement with our result, testing the SM to 0.7 parts per trillion (ppt) and, specifically, bound-state QED corrections to 0.5 parts per million (ppm), their most precise test so far." I am not an expert, but the article in Nature seems of significance regarding Wikipedia's Proton article. Notafluke (talk) 20:21, 23 February 2026 (UTC)

There is content in Proton radius puzzle about that source. We generally want to rely on secondary sources but Nature is a top journal, the team reporting the value is expert, and the issue is no longer controversial. Johnjbarton (talk) 23:51, 23 February 2026 (UTC)

Thank you. Sorry if I overstepped. I had missed the "puzzle " article that you pointed out. Perhaps the main Proton article will be updated if and when CODATA is revised. Notafluke (talk) 04:31, 24 February 2026 (UTC)