Wikipedia:Featured article candidates/Quark/archive4

The following is an archived discussion of a featured article nomination. Please do not modify it. Subsequent comments should be made on the article's talk page or in Wikipedia talk:Featured article candidates. No further edits should be made to this page.

The article was promoted by Karanacs 20:41, 21 July 2009 [1].

Quark[edit]

Nominator(s): —Anonymous Dissident^Talk 07:56, 9 June 2009 (UTC), Headbomb {^ταλκ_{κοντριβς} – WP Physics} 09:02, 16 June 2009 (UTC)[reply]

I am nominating this for featured article because even User:Markus Poessell feels it's ready – and that's something. ;-) In all seriousness, I'd like to thank Markus, TimothyRias, Headbomb, Army1987, and many others for their substantial help with this one. Any of the above should feel free to add their name to the "nominator" category. —Anonymous Dissident^Talk 07:56, 9 June 2009 (UTC)[reply]

Support This article had a number of factual and reference issues at the previous FAC. Since then these have been addressed, and I believe it is now both factually correct, and well referenced, while still fairly accessible. I have, however, made significant edits to this article since the last FAC, so my opinion cannot completely be viewed as independent. (TimothyRias (talk) 13:14, 10 June 2009 (UTC)) −[reply]

Comments -
~~Have a deadlink~~

That is odd, it was OK two days ago, but it appears to be gone. I've removed the link since it was non-vital anyway. (TimothyRias (talk) 15:14, 10 June 2009 (UTC))[reply]

~~Please spell out abbreviations in the notes. Yes, they are linked, but you don't want your readers to leave your article, they might never return. (Specifically I noted BNL, but there may be others)~~

I have spelled out all abreviations I could find, except CRC Press which seems be much more well-known by its abbreviation and SLAC, which is typically also better known by its abbreviation. (TimothyRias (talk) 15:14, 10 June 2009 (UTC))[reply]

Otherwise, sources look okay, links checked out with the link checker tool. Ealdgyth - Talk 14:12, 10 June 2009 (UTC)[reply]

Support As TimothyRias already mentioned: previous versions of this article had significant problems, and I voted "oppose" for its previous two candidacies (complete with a long list of problems I saw). Since then, in my opinion, the article has come a long, long way, and Anonymous Dissident has done excellent work in clearing up the remaining problems, including those raised over the last few months in preparing the article for FAC. I've gone over the current version and its predecessors a number of times with a fine-toothed comb and a magnifying glass (or does that amount to mixing metaphors?), and the physics now looks fine to me. I have also checked all references that were accessible to me (that is, all articles and all but a few of the books). As far as I can see, the article covers all relevant topics, with each given proper weight. Markus Poessel (talk) 09:56, 12 June 2009 (UTC)[reply]

Support ~~Comments~~ looking good, will jot a few notes: Casliber (talk · contribs) 09:55, 14 June 2009 (UTC)[reply]

antiquarks have the same mass, lifetime and spin as their respective quarks - should this be 'lifespan' (i.e. meaning length of life?)?

I believe the term lifetime is, quite arbitrarily, preferred in physics circles. Can't cite it though; maybe someone else can provide deeper insight. —Anonymous Dissident^Talk 10:55, 14 June 2009 (UTC)[reply]

that's cool, I keep thinking of biology articles :) Casliber (talk · contribs) 12:03, 14 June 2009 (UTC)[reply]

~~Most studies conducted on heavier quarks have been performed in artificially created conditions, such as in particle accelerators~~ ~~- given conditions required for their creation, shouldn't this be all studies? (or just studies)?~~

Good catch. Fixed. —Anonymous Dissident^Talk 10:57, 14 June 2009 (UTC)[reply]

This should be most, not all. There are cosmic rays studies, which are natural conditions.Headbomb {^ταλκ_{κοντριβς} – WP Physics} 09:06, 16 June 2009 (UTC)[reply]

That being said, I think the current version is fine.Headbomb {^ταλκ_{κοντριβς} – WP Physics} 09:51, 16 June 2009 (UTC)[reply]

Last thing - I thought adding 'the fundamental building blocks of the atomic nucleus' in the lede after 'proton and neutron' to emphasise just how ubiquitous these are. Not a deal-breaker though.

Comment—There's some good material here and it looks nearly ready to go, but I have still a few issues that may need addressing:
- The lead contains the following: "Up and down quarks have the lowest masses of all quarks, and thus are generally stable and very common in the universe." How does it follow that the lowest mass particle in a family must be very common in the universe? This is not explained in the article (that I could find), and so is uncited.
  - Well, the reason they're very common is given in the same sentence: they're more stable. Higher mass = lesser stability = less common. —Anonymous Dissident^Talk 06:41, 16 June 2009 (UTC)[reply]
    - The reason is that decay means "going to a lower mass". Since these are the least massive, they cannot decay (well the down quark can decay into an up quark because the d is slightly more massive than the u, but that decay only happens in certain condition. See beta decay for details). Headbomb {^ταλκ_{κοντριβς} – WP Physics} 09:18, 16 June 2009 (UTC)[reply]
      - I've placed a note so it should be clearer for readers now.Headbomb {^ταλκ_{κοντριβς} – WP Physics} 09:51, 16 June 2009 (UTC)[reply]
        Perfect. Thank you.—RJH (talk) 22:31, 19 June 2009 (UTC)[reply]
    - Well, not to quibble, but that logic presupposes that the particular particle (or it's decay ancestors) was already very common. I'm not sure that logic follows based solely on the mass. Take positrons, for example. Also, aren't the baryon-to-neutrino and baryon-to-photon ratios very low? I think you need a point of comparison there for the "very common" to make sense..—RJH (talk) 18:32, 16 June 2009 (UTC)[reply]
      - Common as in pretty much everything around us is made of up and down quarks. Headbomb {^ταλκ_{κοντριβς} – WP Physics} 19:05, 16 June 2009 (UTC)[reply]
        I would appreciate it if you would add such a qualification for the reader in order to give a basis of comparison. To me, in astronomical terms, they seem exceptionally rare: the photon-to-baryon ratio is about 10⁹. Most of the universe is a very hard vacuum, and critical density is about six atoms per cubic meter.—RJH (talk) 22:05, 17 June 2009 (UTC)[reply]
- There seems to be some overflow of the Properties content into the Classification section. For example, there are three paragraphs on hadrons in the latter, which would seem to have little bearing on the classification of quarks, but plenty on the properties. There is also a paragraph in the Classification section on the fundamental interactions, which also seems more appropriate for the Properties section. Perhaps the hadron information belongs in a "Hadrons" subsection?
  - Hmm. I think hadrons are part of the quark classification. The Classification section is designed to discuss the relative place of the quark in the scheme of the particle zoo. Discussion of hadrons, their composites, belongs here. The same can be said of the fundamental interactions. Sure, the way quarks actually interact is a property, but the mention of the fundamental interactions in the Classification section describes how "quarks are the only known elementary particles that engage in all four fundamental interactions of contemporary physics". This is part of the classification. —Anonymous Dissident^Talk 03:26, 19 June 2009 (UTC)[reply]
    - I guess I'll reluctantly yield to your logic.—RJH (talk) 22:43, 19 June 2009 (UTC)[reply]
- "A great number of hadrons are known..." If you have lists, why not give a rough number here? More than a hundred?
  - "Hundreds" inserted. —Anonymous Dissident^Talk 06:45, 16 June 2009 (UTC)[reply]
    - Restored "A great number of hadron" (see Talk:Quark#Unproven). Essentially, counting hadrons is not something most people are comfortable with.Headbomb {^ταλκ_{κοντριβς} – WP Physics} 09:20, 16 June 2009 (UTC)[reply]
      - Sorry but what does comfort have to do with this? To me a "great number" is a nearly meaningless expression. C.f. Wikipedia:Manual_of_Style#Unnecessary_vagueness. For example, Paul Davies, is his book Superforce (p. 85) says, "there are literally hundreds of hadrons."—RJH (talk) 18:45, 16 June 2009 (UTC)[reply]
        See Talk:Quark#Unproven for the details. Davies means hadronic resonances. How to count hadrons is something no one agrees on.Headbomb {^ταλκ_{κοντριβς} – WP Physics} 19:02, 16 June 2009 (UTC)[reply]
        That seems even worse. How then should the reader interpret the expression "great number"?—RJH (talk) 22:12, 17 June 2009 (UTC)[reply]
        Normally, I would agree with you, but in the context, I think it's fine: right next to "a great number", we link the reader to two pertinent lists. Attaching any kind of vague value to this will simply provoke 1) more ambiguity or 2) confusion because of the disparities in definition discussed by Headbomb above. —Anonymous Dissident^Talk 23:27, 17 June 2009 (UTC)[reply]
        Well then it might be sufficient to just cite somebody notable using that expression, or something comparable. Would that work for you?—RJH (talk) 22:40, 19 June 2009 (UTC)[reply]
        I'm not sure if I can cite someone notable saying that phrase verbatim, but I could quite simply find a source mentioning that there are a great number of hadrons. —Anonymous Dissident^Talk 13:17, 22 June 2009 (UTC)[reply]
        That would work for me. I found a source saying there are a huge number, but I was wrong about Paul Davies's quote so I'd prefer that you guys find the source. Thanks.—RJH (talk) 16:21, 22 June 2009 (UTC)[reply]
        Well, as I said, we are pointing readers to the list of baryons and list of mesons so they can see for themselves. I really don't see why we need a source to specifically opine that there are a great number of them.Headbomb {^ταλκ_{κοντριβς} – WP Physics} 17:03, 22 June 2009 (UTC)[reply]
        Well, frankly, I looked and I did not see a great number, so the statement seems flat out absurd. A few hundred hadrons does not constitute a "great number". It like to see a source for this assertion, or have it removed.—RJH (talk) 23:04, 22 June 2009 (UTC)[reply]
        I guess that depends on your definition of 'great number' in the context of "one, two, many" 100+ is a huge number. More than 100 is a huge number for particles that at one time were thought to be fundamental (which is the context in which this statement was made). Compared to the number of particles in the observable universe it is negligable. (TimothyRias (talk) 06:39, 23 June 2009 (UTC))[reply]
- ~~"...the formation of composite particles known as hadrons in a process of hadronization." Please fix this ambiguity.~~
  - Well, I've clipped the redundancy; it says ""...the formation of composite particles known as hadrons" now. Is this the problem? I don't think overt detail is appropriate for this section, and we have the section link for a reason. —Anonymous Dissident^Talk 06:50, 16 June 2009 (UTC)[reply]
    - That's fine, thanks.—RJH (talk) 18:45, 16 June 2009 (UTC)[reply]
- ~~"Several experiments claimed to have proven the existence of tetraquarks and pentaquarks..." Experiments made the claim?~~
  - Clipped that, and the surrounding two sentences. The construction was awkward, and went into too much detail. The claims are just that: claims. "but not proven" is enough. —Anonymous Dissident^Talk 07:03, 16 June 2009 (UTC)[reply]
- ~~Please clarify "2008 Tevatron" through a wikilink or a description.~~
  - Done. —Anonymous Dissident^Talk 07:07, 16 June 2009 (UTC)[reply]
- "...they typically annihilate each other very quickly within the interior of the hadron." Please provide a value/estimate to clue the reader into the time scale here, and so avoid unnecessary vagueness. Is it 0.1 seconds or 10^-20 seconds, for example?

Since the life-time is here mostly controlled by the Heisenberg uncertainty relation, I'd expect the time scale to be of the order of an inverse quark mass. So, your 10^-20 is the right ball park maybe a few orders of magnitude lower still. However, if we're going to include such a figure in the article, it needs a ref. Anybody know if the current refs metnion anything about the time scale? (TimothyRias (talk) 08:49, 19 June 2009 (UTC))[reply]

I for one couldn't find anything. 10^-20 does sound approximately reasonable – I know I've read a figure like 10^-18 somewhere. —Anonymous Dissident^Talk 08:57, 19 June 2009 (UTC)[reply]

Would it be possible to cite a notable source saying it happens "very quickly"? Or perhaps you could explain the time scale in terms of the "Heisenberg interval". Thanks.—RJH (talk) 16:21, 22 June 2009 (UTC)[reply]

IIRC, once upon a time (about one year ago) the article said that happens "about a septillion or a thousand billion billion times each second", with a source. I replaced that with "about 10²⁴ times". ~~Would anyone with a less slow Internet connection than mine bother to check the article history for that?~~ --A. di M. (formerly Army1987) — Deeds, not words. 20:48, 22 June 2009 (UTC)[reply]

Here it is. So it's 10⁻²⁴ seconds... Does anyone have access to that source? --A. di M. (formerly Army1987) — Deeds, not words. 10:08, 23 June 2009 (UTC)[reply]

Actualy that is about the number of virtual gluon exchanges between two quarks. Nothing is said about the lifetime of virtual quark pairs inside a hadron, unfortunately. Nice try though. (TimothyRias (talk) 11:25, 23 June 2009 (UTC))[reply]

- "has been postulated", "It has been conjectured that," "It is believed that", "Such sea quarks are commonly assumed to form", &c. I think these may conflict with Wikipedia:Avoid weasel words. The use of "physics community" in the History section seems less weasely, at least to me.
  - Removed all but one that I thought was necessary. —Anonymous Dissident^Talk 03:22, 19 June 2009 (UTC)[reply]
    - Close enough. Thank you.—RJH (talk) 22:34, 19 June 2009 (UTC)[reply]
- ~~"perhaps comparable to those found in neutron stars" Why the 'perhaps'? Is this a gentlemanly perhaps, or a theoretical perhaps?~~
  - Theoretical. —Anonymous Dissident^Talk 07:57, 16 June 2009 (UTC)[reply]
Thank you.—RJH (talk) 16:51, 14 June 2009 (UTC)[reply]

Support Somehow I missed the FAC and now just noticed it. I worked on this, and support the article as an FA, as I'm pretty satisfied and proud of the job we did. I don't think there's anymore that could be said about quarks in this article, and what we said is, IMO, well-said, well-structured, with something for every type of reader out there. Headbomb {^ταλκ_{κοντριβς} – WP Physics} 09:01, 16 June 2009 (UTC)[reply]

Oppose for now. I have initiated a line-by-line prose review which, per this suggestion by SandyGeorgia, is being listed at the article's talk page. Please respond to individual concerns there. --Cryptic C62 · Talk 18:23, 17 June 2009 (UTC) Support. There are a couple of ongoing discussions on the talk page as well as a few "optional" points that I brought up, but other than that I am completely satisfied. This article is the embodiment of the spirit of the Wikipedia model: a handful of users around the world collaborating and persevering to create the best possible article. Good work, everyone. --Cryptic C62 · Talk 16:41, 20 July 2009 (UTC)[reply]
It would be a lot more convenient if you listed which of your grievances remains unadressed here. Because right now, it's really hard to gauge why you are opposing. Headbomb {^ταλκ_{κοντριβς} – WP Physics} 03:58, 20 June 2009 (UTC)[reply]
I'm not done reviewing the article. As issues are addressed, I will strike them. --Cryptic C62 · Talk 04:06, 20 June 2009 (UTC)[reply]
For the closer: we're slowly chugging through the points listed on the talk page. Progress is being made and the FAC has not stagnated (just kind of half taken place on the talk page). —Anonymous Dissident^Talk 13:18, 28 June 2009 (UTC)[reply]
Although there are several little issues being discussed on the talk page, there are two that I'm really concerned with: First is the use of the Schombert ref, second is that there seems to be no consensus on what material the "Weak interaction" section should present. --Cryptic C62 · Talk 21:03, 7 July 2009 (UTC)[reply]
I think we've come out pretty clear on the second one. I think we're all somewhat agreed now. —Anonymous Dissident^Talk 14:42, 8 July 2009 (UTC)[reply]
There is an ongoing discussion about the CKM / PMNS matrices. Very little has been done to address my concerns that the "Weak interaction" section does not make it clear whether the decays are one-way or two-way processes. --Cryptic C62 · Talk 16:01, 8 July 2009 (UTC)[reply]
How can "[b]y absorbing or emitting a W boson, any up-type quark (up, charm and top quarks) can change into any down-type quark (down, strange and bottom quarks) and vice versa" [emphasis added] be interpreted as stating that it's a one-way process? --A. di M. (talk) 16:18, 8 July 2009 (UTC)[reply]

One of my concerns was with the presentation of the CKM matrix, though I see that this has been resolved with the addition of "(or vice versa)". The pictorial representation of the matrix is misleading with its one-way arrows. Properties issue #8 is also unresolved: Headbomb proposed a solution but then reverted is as being "misleading". --Cryptic C62 · Talk 16:26, 8 July 2009 (UTC)[reply]
How is issue #8 not resolved. You just said that this was resolved by adding (or vice versa)? As for the CKM image, it illustrate quark decays, and is quite clear about it. I don't see what could possibly be confusing/misleading about it.Headbomb {^ταλκ_{κοντριβς} – WP Physics} 17:09, 8 July 2009 (UTC)[reply]
No, issue #10 was (mostly) resolved by the addition of "(or vice versa)"; I have struck the relevant parts of it. Issue #8, regarding the difference between up-to-down decay and down-to-up decay, is still unresolved. --Cryptic C62 · Talk 18:52, 8 July 2009 (UTC)[reply]
The diagram is very clearly is about the decays and not the reverse process. (And up to down isn't a decay).Headbomb {^ταλκ_{κοντριβς} – WP Physics} 21:51, 8 July 2009 (UTC)[reply]
Actually, see the first sentence of "Positron emission" and of "Electron capture"; but that's another story. So "up to down isn't a decay" isn't always true, but cases when it's not true are way beyond the scope of this article. --A. di M. (talk) 01:35, 9 July 2009 (UTC)[reply]
The nucleus decays, not the quarks.Headbomb {^ταλκ_{κοντριβς} – WP Physics} 03:51, 9 July 2009 (UTC)[reply]

Support. The article is even in better shape than when I took the last careful look at it more than a month ago. --A. di M. (formerly Army1987) — Deeds, not words. 15:33, 19 June 2009 (UTC)[reply]

Comment. A. di M.'s recent rewriting of the 1st paragraph of the lead[2] got rid of the simple explanation for what a quark is. Quarks are the building blocks of protons and neutrons. If the lead doesn't state that clearly, I can't support the article. It now says only that quarks are "found within" protons and neutrons. Please either rewrite it or revert it so that someone who isn't a physicist can read the article and learn what a quark is. Kaldari (talk) 16:46, 23 June 2009 (UTC)[reply]

I've reverted this paragraph for now. Feel free to try another rewrite if you like (or revert to the previous version if you object). Kaldari (talk) 16:57, 23 June 2009 (UTC)[reply]

Oppose on image concerns from someone with only high-school Physics knowledge:

File:Charmed-dia-w.png: the original emails in User:Aarchiba/Brookhaven permission should be forwarded to the OTRS and the ticket attached; however, the wordings contain amibiguity. "Usage of the image(s) constitutes your agreement to the terms of Brookhaven National Laboratory's image licensing policy": http://www.bnl.gov/bnlweb/images_legal.html says nothing about public domain or such. In fact, its wordings are more in line with fair use, especially in regards with the sections "License Granted by BNL", "No Alterations", "Publication Right", and "Indemnification".
Nominated for deletion at commons:Commons:Deletion requests/File:Charmed-dia-w.png. Oppose will be stricken on resolution of this request (either keep or delete). Jappalang (talk) 01:51, 3 July 2009 (UTC)[reply]

The image is public domain. If you want to upload it on the fair use image space and change the license to fair use in the meantime, go ahead, but please don't oppose based on a trivial detail like "is this image public domain or fair use".Headbomb {^ταλκ_{κοντριβς} – WP Physics} 03:49, 3 July 2009 (UTC)[reply]

File:Beta Negative Decay.svg: only knowing elementary physics, is this sort of diagram drawn on evidence (i.e. does it matter if the W- line is drawn as a sine wave or not)? If yes, perhaps a reference source should be provided.
In Feynman diagrams, fermions are conventionally drawn as straight lines, photons and weak bosons as wavy lines but the latter with larger wiggles, and gluons as "springs". See the pictures in Feynman diagram and in [3]. So long as each particle is labeled appropriately it doesn't matter terribly, but I don't see the need to either deviate from the standard convention or provide a reference for it: after all the article is about quarks, not about Feynman diagrams. --A. di M. (formerly Army1987) — Deeds, not words. 12:10, 1 July 2009 (UTC)[reply]
~~File:Quark decays.svg: please give at least a description of what this image is supposed to represent~~
Provided a short description of the image.
~~File:QCDphasediagram.svg: what does "QCD" stand for? I think this requires a source [so one can readily verify the temp-density relationship between the properties(?)].~~
Added a reference. (TimothyRias (talk) 11:36, 1 July 2009 (UTC))[reply]

Other images are appropriately licensed. Jappalang (talk) 08:58, 1 July 2009 (UTC)[reply]

support I read this in detail some time ago, and thought I'd voted then, but can't see it above. A surprisingly accessible article on a difficult topic jimfbleak (talk) 07:00, 3 July 2009 (UTC)[reply]

Comment: The term Standard Model in the first paragraph requires the words "of particle physics" after it, for someone who thinks that the standard model comes with a cd player, retractable seat belts and an air bag.Amandajm (talk) 15:40, 4 July 2009 (UTC)[reply]

I think the context, the capital S and M, and the link are enough. "The only particles in the Standard Model of particle physics" sounds quite redundant to me. What do you others think? --A. di M. (formerly Army1987) — Deeds, not words. 16:30, 4 July 2009 (UTC)[reply]

Yes, I agree that it sounds repetitious. However, if one is completely ignorant of the fact that such a thing as a Standard Model of Particle Physics exists, then one needs to have it included, for clarity. I would tend to capitalise the whole lot, as I have done here. Amandajm (talk) 11:24, 8 July 2009 (UTC)[reply]

For some reason, "Standard Model" is a proper name and "particle physics" isn't. I know that's weird, but see Wikipedia_talk:Manual_of_Style/Archive_108#Capitals for scientific theories? Why? and Wikipedia_talk:Manual_of_Style/Archive_109#Follow the sources. --A. di M. (talk) 13:34, 8 July 2009 (UTC)[reply]

Comment. Done; thanks. Alt text is needed for readers who can't see the images (see WP:ALT and WP:FACR #3). I added alt text for the lead image to illustrate the process; could someone else please do the other images? Thanks. Eubulides (talk) 18:35, 7 July 2009 (UTC)[reply]
- I've written some of them, but I'm not familiar with that stuff, and I'm not sure of whether there's too much or too little detail in them. Could you review them? --A. di M. (talk) 13:34, 8 July 2009 (UTC)[reply]
  - The were a very good first cut. I tweaked them a bit, mostly for brevity. ~~Alt text still needed for the other images, and for the math.~~ Thanks. Eubulides (talk) 18:41, 15 July 2009 (UTC)[reply]
    - Thanks for finishing this up. Eubulides (talk) 20:22, 19 July 2009 (UTC)[reply]

The above discussion is preserved as an archive. Please do not modify it. No further edits should be made to this page.