Talk:Proton

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[edit] the down quark

Why doesn't it decay into an up quark? Quantum Burrito 22:50, 5 January 2007 (UTC)

[edit] Magnetic moment

It would be nice to have some information about the magnetic moment of the proton, (numerical value, theoretical understanding, etc.). The only reference to it I've seen in the article is in the section about the antiproton.

This is not a particularly interesting fact....

Interesting fact: the ratio of the mass of the proton to the mass of the electron is to 2 parts in 100000 equal to 6*pi^5.

I personally think that this is an interesting fact, of course I am almost finished with a physics degree.

No? Well, items relating proton mass to Britney Spears are pretty short on the ground. I guess the fact that the product of the electrical permitivity and magnetic permeability of free space were very close [within experimental precision equal to] to the reciprocal of the square of the speed of light is also exceedingly boring. Except that the notorious crank Maxwell based electromagnetic field theory from this observation. So if the almost non-mentioned fact that the mass of the proton to the electron is to a high degree of precision a simple multiple of a simple power of pi doesn't spark some degree of interest in you, then I guess you're just not cut out to be a physicist. :-)

The age the Universe had when the song ATWA from System of a Down's [[Toxicity_(album)

|Toxicity]] when it was released was 3*pi^30 times the duration of the song itself, so what?


Roadrunner is correct, and I'm afraid you, 81.86.154.69, are not. Playing with things like N*pi^M, or change pi for e, or whatever, you can get almost any number. This has nothing to do with Maxwell's observation for the "product of the ...", because indeed it is not true, Maxwell was not doing numerology (as you are doing), he explicitly calculated the speed of an electromagnetic wave (= 1/sqrt(mu * epsilon) ) and compared it with the speed of light.

Moreover, today we know that protons are made of quarks, and that their mass is not the sum of the masses of the three quarks, because the binding energy amounts for a lot more. So there is, no relationship foreseen whatsoever.

What's more, 2002 CODATA's value for proton-electron mass ratio is 1836.15267261±0.00000085, and 6*pi^5 is 1836,1181087116, forty thousand times the uncertainity less than that.--Army1987 15:56, 19 July 2005 (UTC)


JBC

Hello.

I´m a young spanish student and i´d like to give you my congratulations for this wonderfull encyclopedia,i´m really surprised of its whole content. Before beginning i´d like to give you my sorries because my english is not so good as i´d like it to be,but i hope i will be able to explain my self. Anyway be sure that i understand whatever in this encyclopedia you´re talking about.

Cause my low knowledge about Quantum mechanics (in comparison whith you but not whith my friends) i imagine that my doubt will not supose you a great work.

I'm confused about what you explain in Proton page. Here i can read that "the charge of proton must be equal to the charge of electron", naturally, to get forcing equilibrium. Some lines down i can read that "the positron has the same magnitud charge as the electron but oposite in sign". My doubt stribes in the following question: if the positron is the antiparticle of the electron and they have the same but oposite charge, and the charge of proton must beequal to the charge of electron (and, naturally, basing my self in the fact that positron, charge +, electron, charge -; that means to me that charges are also oposite), here i have a contradiction for my mental schema. This make me think by any way that protons and positrons are the same particle, what i´m sure is not true.

So, concluding, my answer is: What kind of phenomenon i unknow makes different the behavior of proton and positron front the electron?

Thnks, :)

The mass of a proton is much larger than that of a positron. - Patrick 20:04, 11 Dec 2003 (UTC)
Unlike the positron, the proton feels the strong nuclear force. —User:Herbee 2004-02-10

[edit] Disambiguation

This page should be a disambiguation page and the stuff should be moved to Proton (physics). Bensaccount 01:20, 28 Feb 2004 (UTC)

I disagree. I mean, the physics related "Proton" is more likely to be the wanted subject of the artile over the "proton" title. So, i think there should be a direct redirection to the "proton (physics)" article, and a link to the disambiguation page. Kieff 04:59, Apr 11, 2004 (UTC)

You are right. My mistake. Bensaccount 17:32, 16 May 2004 (UTC)

[edit] Mass in eV

I'm a little confused, why is mass measured in eV?

It's a shorthand that physicists like to use. Particle physicist types are generally concerned with calculating and measuring energies rather than masses in particle reactions and such, and so they get to a rest mass by converting the rest energy with a factor of c2 (good ol' E=mc2). Being lazy, however, they tend to drop factors of c (and h, Planck's constant) when doing calculations, sticking them back in when it's necessary to actually get a number out.
However, this article isn't written for physicists, so I'll add the c2... Carmelbuck 03:56, 12 Nov 2004 (UTC)
It's not laziness. c = 1 is part of a perfectly acceptable and useful system of units. -- Xerxes 03:34, 2004 Nov 13 (UTC)
I don't knof if Xerxes' quote was a joke, but c=1 does not mean that it isn't there. It is still correct to include it. Pdbailey 04:06, 23 Nov 2004 (UTC)

News! teleronci: Newly calculated elementary particle of rest mass = 1.15819171.10^-30 kg which in is included as integer value in the rest mass of proton and neutron. (Source: Meissner, R.:Das Teleronki-Modell..., Aachen: Shaker-Verlag 2001.)

[edit] Removing argument about proton charge relative to electron

I'm removing this:

"Because the electromagnetic force is many orders of magnitude stronger than the gravitational force, the charge on the proton must be equal and opposite to the charge on the electron. Otherwise, the net repulsion of having an excess of positive or negative charge would cause a noticeable expansion effect on the universe, and indeed any gravitationally aggregated matter (planets, stars, etc.)."

The argument that we must be living in an approximately charge-neutral observable universe is correct. The conclusion that protons and electrons have the same charge makes the assumption that they occur in equal numbers. I see no basis for such an assumption; they could have different charges and occur in correspondingly different numbers. This would not be a "coincidence" cosmologically if there were a good reason for charge neutrality; the particles we end up with would have been constrained by that.

There are good theoretical reasons to believe that the charges of protons and electrons are exactly equal; perhaps such belong on the page about electric charge.

Somebody restored the above claim of evidence of charge equality to the page. It appears to be fallacious, and whoever restored it did not address the dispute on this talk page. So I'm taking it back out. Dhochron 22:01, 26 October 2005 (UTC)

[edit] Protons and electrons

Does anyone know if there are any theories to the possibility that the Down Quark is composed of an Up Quark and an electron? I once heard that when a Proton and Electron mix it produces a neutron. So if this is true then if you mix an Up Quark and an electron it must form a down quark...I am not sure though. - BlackWidower

[edit] History dispute

Eugene Goldstein discovered the proton. Bayerischermann 00:26, 26 October 2005 (UTC)

Do you have evidence for this claim ? According to PBS, Encarta and ScienceWorld , Rutherford discovered the proton.
---
The claim is incorrect. Canal rays are positive ions not protons or bare nuclei (except in the case of hydrogen). See, for example the presentation of the 1919 Nobel Prize in Physics to Stark:
In the year 1886 Goldstein discovered a new kind of rays in discharge tubes containing rarefied gas, the study of which has become extremely important to our knowledge of the physical properties of atoms and molecules. In view of the manner of their formation Goldstein called them canal rays. It was proved by the research of W. Wien and J.J. Thomson that the majority of these are composed of positively charged atoms of the gas in the discharge tube, which move along the beam at a very high velocity. (my emphasis)
As an entity distinct from ordinary ions, it would be incorrect to say that the observation of canal rays amounted to the discovery of protons. Rather, it was Rutherford who:
1) determined that the proton is small and dense
2) proposed that it makes up the nuclei of all atoms
which is really what defines the proton.
Anyway, the history paragraph could add a bit on Goldstein without explicitly claiming he "discovered" the proton. -- Xerxes 14:51, 26 October 2005 (UTC)
It's not my claim, it's what both my Chemistry teacher and my textbook (Wilbrahm, Anton C, Dennis D Staley, and Michael S Matta 1995. Chemistry. Menlo Park, California: Addison-Wesley) say. In particular, it says "In 1886 E. Goldstein, using a cathode ray tube in which the cathode had holes, observed rays traveling in the opposite direction to the cathode ray. These rays, shown in figure 4.5, contain positively charged particles and are called canal rays." and to the left of Figure 4.5: "If the gas in the cathode ray tube was hydrogen, the canal rays would be made up of protons; after hydrogen gas atoms lose electrons at the cathode, only protons remain to form the canal ray." In the book, this is listed as the first discovery of protons. Rutherford was after Goldstein, and I never even suggested that Goldstein influenced anybody. Bayerischermann 21:49, 26 October 2005 (UTC)
Xerxes summed it up nicely, i.e. observing canal rays is not equivalent to discovering protons, and something on Goldstein should be added. Since only one source seems to claim Goldstein discovered the proton, and the remaining ones claim Rutherford, I would suggest -- without further evidence -- that the one source was wrong Salsb 21:58, 26 October 2005 (UTC)

[edit] "This equality has been tested to one part in 10-8"

I'm no expert, but one part in 10-8 seems like an awfully big uncertainty. Shouldn't this be one part in 108?

[edit] Cut and paste

The following was apparently cut-and-pasted from an AIP news article. In its present form, it is certainly unsuitable for the article; perhaps it would be more suitable (heavily edited) in a HAPPEx article? In addition, the original content author demands a specific form of credit for reposting this content.

...

-- Xerxes 15:36, 2 May 2006 (UTC)

I assume that was a copyright violation, so I've deleted it here too. Melchoir 16:17, 2 May 2006 (UTC)

[edit] Diameter?

This seems a bit silly, and I was a physics major, but... what's the diameter of the proton? We can all recite the characteristic size of the hydrogen atom (1 angstrom, 10^-8 cm, 10^-10 m), and it's said that the proton is not pointlike but has some diameter. So what is it? I found one source that suggested, without attribution, that it was on the order of 10^-15 m. Is this firm? Is it quantum-uncertain? Should it be part of the basic attributes like mass, charge, etc.? Google searches for "proton diameter" were not conclusive.Eh Nonymous 20:06, 23 May 2006 (UTC)

It's a bit hard to say what "proton diameter" means. Most experiments seem focused on determining the "proton root-mean-squared charge radius". This value is not very well known, but is about 0.87 fm. So by that measure, the proton diameter is about a fermi and a half. -- Xerxes 21:07, 23 May 2006 (UTC)

The propton-diameter mentioned now under properties (1.5*10-15 m.) is half the electron radius mentioned in Mass_of_electron. Unfortunately I don't know what to trust, but probably something is not OK. (Jan-Willem, 21 July 2006)

[edit] Original research vs. suppression

These references at Further reading section were deleted as original research:

  • The following analysis addresses the problem of proton creation and it's integrated in the concepts of the Physics of Creation:
Aspden, Harold (2003), Physics of Creation: The Creation of the Proton (Chapter 4), PhD. Physics - University of Cambridge [1953], UK [pdf file]
Aspden, Harold (2005) Aspden Research Papers Nº4: The Creation of the Proton
"The value that they [Aspden and Eagles] calculate is remarkably close to our experimentally measured value (i.e. within two standard deviations)This is even more curious when one notes that they published this result several years before direct precision measurements of this ratio had begun." R. S. Van Dyck, Jr., F. L. Moore, D. L. Farnham and P. B. Schwinberg in Int. J. Mass Spectrometry and Ion Processes, 66, p. 327, 1985.

This author seems to have some peer-review published papers ('Physics Today', 'Journal of Applied Physics', 'American Journal of Physics', 'Physics Letters', 'Hadronic Journal', 'Physics Essays', Physics Education', etc.) [1] and his work is mentioned by other members of the scientific community (as quoted above). And now his work cannot be presented in the related Wikipedia's articles??? What policy is this?! --88.214.171.194 05:26, 8 September 2006 (UTC)

The paper you refer to has been superseded by a paper from the same authors, in which they report a better value of the ratio, which seems to rule out the value given by Aspden. (Phys. Rev. Lett., Vol. 7075, p. 3598) They also make no mention of Aspden in this newer paper.
Moreover, the particular writings you link to are clearly original research. (Self-published works constitute original research.) The fact that the author has been published in legitimate journals -- apparently on other topics -- does not mean that all of his publications are acceptable. MOBle 05:41, 8 September 2006 (UTC)
It is on volume 75 [2], and the measured value "via Penning Trap Mass Spectroscopy" of 1836.152 666 5(40) (1995, 20 years later) is slightly above 1836.152, as it was recorded in Aspden's 1975 paper of 1836.15232 (H. Aspden & D. M. Eagles, Il Nuovo Cimento, 30A, 235 (1975)) [3], a theoretical value derived from his aether theory (not from wide expensive experiments). Still, how was he able to derive this value so close to the experimental result and not be considered fit as a resource to a Wikipedia article? Worse, discarding his work when you donnot have other theorie(s) than can predict such accuracy? Interesting that in 1960 and 1977 Dr. Aspden already published about the "electrostatic spin" (described as 'aether spin' induced by electrostatic charge [4]) before its discovery was announced by the University of California in April 2003 [5] (note that this phenomenon could not be explained by available theory at the time of its discovery). Something strange is going on in the Physics field... and I am not even a physicist (people like me is just start noticing these unbelievable things). Really, I sense you should give a better look to his 2005 paper (above). Thank you for your attention. --88.214.171.194 06:29, 8 September 2006 (UTC)
As you point out, Aspden's prediction was 1836.15232. This is 87 standard deviations away from the accepted value of 1836.1526665(40) cited above. That essentially means that Aspden's value is ruled out scientifically. That is the reason it should be discarded: experiment proved it wrong. His theories don't seem to explain anything.
You may find his writings very interesting. You may even be convinced by his claims that he's predicted unusual physical effects before they were discovered by others. However, until his claims are verified by other experts and published in reputable sources, they should not be included in Wikipedia. MOBle 06:58, 8 September 2006 (UTC)
Neither the mentioned experiments were conceived to test his theories (or the whole work), neither the result presented in his 1975 paper (and you have no other) was calculated in order to reflect the type of high precision measurement of such experiments (therefore he presents approximate values, yet accurate as proven by the 1985 measurement). Nevertheless, even the value you state as an "accepted value" seems to be different from the value given by CODATA (Rev. of Mod. Phys., vol 77, Jan 2005), and I think they are not the only values which were given to the measurement of the proton-electron mass-ratio through the last two decades. Last, I have already understood that the verification you mention to his "claims" will not be conducted, at least not by the current "experts", as in the aether vs. Relativity subtle war... If this was to be the case, it would have been conducted-done more than 10 years ago at least (since his work has already more that 40 years of research and the Van Dyck's and fellows measurement confirmation occured about 21 years ago). Perhaps in a next generation of Physicists! :) --88.214.171.194 09:12, 8 September 2006 (UTC)

[edit] Request

Is it possible to make the definition simpler to read.......Thank You —The preceding unsigned comment was added by 129.44.215.148 (talk • contribs) 22:14, 10 September 2006 (UTC)

[edit] Density

The proton has a density of about 2.31 × 1017 kg m−3.

That would imply a proton radius of 1.2 fermi—not one of the values mentioned here. Three significant digits also seems a bit too much. Probably somebody playing with their calculator. Since density is normally not a hot topic with particles, I removed the sentence.
—Herbee 20:35, 4 December 2006 (UTC)

I think the density might be a useful fact for general readers, because it helps put into perspective how "empty" ordinary matter is. Itub 20:54, 7 December 2006 (UTC)
Such a perspective might be useful, but the proton article wouldn't be an obvious place to look for information on the emptiness of ordinary matter. The Orders of magnitude (density) article already contains an entry for the proton.
—Herbee 00:25, 8 December 2006 (UTC)
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