Talk:Quark

From Wikipedia, the free encyclopedia

This article was externally reviewed on December 14, 2005 by Nature. No significant errors or major omissions were found.

Quark has been listed as a good article under the good-article criteria. If you can improve it further, please do.
If it no longer meets these criteria, you can delist it, or ask for a review.

Physics Portal

This article is within the scope of WikiProject Physics, which collaborates on articles related to physics.

This article has been rated as GA-Class on the assessment scale.

Top

This article is on a subject of Top importance within physics.

Help with this template

This article has been rated but has no comments. If appropriate, please review the article and leave comments here to identify the strengths and weaknesses of the article and what work it will need.

Quark is included in the 2006 Wikipedia CD Selection, or is a candidate for inclusion in the next version. Please maintain high quality standards and, if possible, stick to GFDL-compatible images.

This article has been selected for Version 0.5 and the next release version of Wikipedia. This Natsci article has been rated GA-Class on the assessment scale.

This article is a former featured article candidate. Please view its sub-page to see why the nomination failed. For older candidates, please check the archive.

Quark has had a peer review by Wikipedia editors which is now archived. It may contain ideas you can use to improve this article.

[edit] Alternative names for quarks

I don't think it's a good idea to include fringe names for the higher-generation quarks. Although there was some legitimate discussion about whether the top and bottom should be called truth and beauty, there was never any significant movement to name the strange anything other than strange. In fact, the term strangeness pre-dates the whole quark model. The extra names are simply confusing to the average reader; if they remain in the article at all, I suggest that they be moved to the History section. -- Xerxes 17:04, 2004 Jul 21 (UTC)

Took this out again:

Top and Bottom quarks were also known as Truth and Beauty, though this usage has fallen into disfavor. Strange quark has also been referred to as "Sideways"

Will continue to take out unless somebody can provide a reference. Here are the results of a google scholar search:

"beauty quark" = 206, "bottom quark" = 3570

"truth quark" = 17, "top quark" = 14600

"sideways quark" = 0, "strange quark" = 7870

OK, admittedly google search isn't the most definitive source, but SPIRES won't let you do a phrase search. The results are basically the same there anyway. -- Xerxes 19:11, 2005 August 1 (UTC)

Truth and beauty were important historically. Sideways I've never heard, and I think it may just be made up--strange particles were discovered and called strange before quark theory. -- SCZenz 20:57, 1 August 2005 (UTC)

Lewis Carroll Epstein uses the "truth" and "beauty" names in his classic "Thinking Physics," still in print and available on amazon.com, etc. Scrutchfield

The manchester physics series textbook from 1992 talks about truth and beauty quantum numbers, representing number of top quarks and bottom quarks. Google search is not at all definitive! LeBofSportif 10:52, 12 May 2006 (UTC)

The quantum numbers of the bottom and top quarks are sometimes still called truth and beauty (especially if you're advertsing a conference on the subject). This is due to the awkwardness of the alternate terms "bottomness" and "topness". The quarks are not so-called. -- Xerxes 16:25, 12 May 2006 (UTC)

I have a deck of cards from CERN, printed in their anniversary year 2004. On clubs 10 one can read: Particles - quarks - beauty, strange, down - top, charm, up. I doubt this is a valid reference though... :-) Google gives 92 hits on "beauty quark" inurl:cern, some of them are really official press releases. Google gives 1660 hits on "bottom quark" inurl:cern. My wife was courious about the "beauty quark", and I think it's bad Wikipedia gives no information on it. Maybe it could be a separate article on alternative quark names? tobixen 23:17, 9 August 2006 (UTC)

we should mention "truth" and "beauty" here for sure, and we should redirect those names to the right places. -- SCZenz 23:34, 9 August 2006 (UTC)

[edit] Disambiguation

At first when I saw the table of quarks with the up, down, etc., I thought it was a joke or crank. I continued to read the article, and I realized it wasn’t!! --Merovingian

It would be nice if this page was disambiguated. I would propose a format as seen in Cream. Any objections? --Bluetulip 11:25, 9 Mar 2004 (UTC)

~~It would probably be a good idea to create an explicit page for Quark (disambiguation) and move the extra bits from here to there.~~ Done. --Phil 12:09, Mar 9, 2004 (UTC)

[edit] Quark, son of Keldar

I started an article on the Star Trek character Nog, nephew of Quark, then I clicked the Quark link and wound up here (I'll disambig at the Nog article today if I have time).

I'm wondering if maybe it would be better to move the disambiguation in this quark particle article up to the top of the page. I've seen pages on Wikipedia where the disambig is at the top, like the articles on Paris, Jupiter, etc., but I've also seen at the bottom, like on this one. Is their a standard policy on this? ShutterBugTrekker 16:48, 14 Jan 2004 (UTC)

i always assumed that it was standard to have it on the top. maybe whoever wrote thid goofed

24.70.95.203 23:13, 16 July 2006 (UTC)

[edit] CERN Experiment

The article now states: "One of the experiment in the CERN showed, that only 3 generation of the quarks exists. (From the resonance-width of Z boson.)"(sic) Which experiment, when? --Phil 14:09, Mar 8, 2004 (UTC)

Cured. At least, reference given. --Andrew 05:28, Apr 23, 2004 (UTC)

[edit] Request from anon user

I have moved the following request from an anon user out of the article and placed it here for discussion. - Tεx τ urε 05:12, 5 Aug 2004 (UTC)

They are one of the two families of spin-1/2 fermions (can someone please clarify if this means spin=+1/2 or spin=-1/2)

Spin 1/2 particles can have either +1/2 or -1/2. In general, a spin-j particle can take on spin states anywhere from -j to j in increments of 1. -- Xerxes 17:53, 2004 Aug 5 (UTC)

[edit] Up & Down Quark Mass or Charge Problem?

Here are the masses and charges for quarks.

Up quark (1-5) (2/3) Down quark (3-9) (-1/3) Strange quark (75-170) (-1/3) Charm quark (1,150-1,350) (2/3) Bottom quark (4,000-4,400) (-1/3) Top quark (174,000) (2/3)

As you can see from this table, the quarks are arrayed in order from light to heavy, starting with the up quark. You should notice an irregularity with the up and down quarks compared to the others.

The top quark has charge of 2/3 and can decay into a bottom quark with a charge of -1/3. The bottom quark can decay into a charm quark with a charge of 2/3. The charm quark can decay into a strange quark with a charge of -1/3.

As you can see, a pattern is emerging (2/3, -1/3, 2/3, -1/3) which suggests that the next quark will have a charge of 2/3. But the next quark is a down quark with a charge of -1/3.

Could it be possible that either

an up quark has a charge of -1/3 and a down quark has a charge of 2/3

an up quark has a mass of 3-9 and a down quark has a mass of 1-5.

therefore restoring the pattern?

No. Xerxes

How is it that these properties were attributed to these quarks in the first place?

It's a complicated combination of experiment, theory and lattice calculations. See PDG Note on Quark Masses for an extended discussion. In particular, the u/d ratio can be determined in chiral perturbation theory as a ratio of sums of squares hadron masses. The physical value is around 1/2. Xerxes 15:44, 2004 Aug 27 (UTC)

[edit] The Brookhaven photograph

This is a bubble chamber photograph of Samios and Palmer, from early 1974. They believed at the time that it was a nakedly charmed baryon, but they were unable to eliminate all other hypotheticals, nor find a second example. Plus, they were using a new machine, and nervous about calibration. Even after the November Revolution, they were tentative about what they found. I presume that later discoveries have retroactively resolved the particle's identity.--192.35.35.34 17:11, 3 Feb 2005 (UTC)

The PDG entry on the Σ_c⁺⁺ includes references, of course. The earliest is the one with the photograph. Its status was uncertain as late as 1982. I did not pursue the history of this particle any further.--192.35.35.36 23:37, 7 Feb 2005 (UTC)

[edit] Antiquark article

The Antiquark stub has been listed as VfD at Wikipedia:Votes_for_deletion/Log/2005_May_23#Antiquark. Vote Keep or Delete at this link. Irpen 22:34, May 23, 2005 (UTC)

[edit] Gluons

Should gluons be mentioned in this article? A gluon is a hypothetical neutral, massless particle believed to bind together quarks to form hadrons. → JarlaxleArtemis 01:44, Jun 2, 2005 (UTC)

Gluons are not hypothetical; they are observed (albeit indirectly) in three-jet events. I don't think it's crucial to have a direct link to gluons in this article, since you can get to them by clicking any of the numerous links to hadron- and QCD-related articles. But if somebody can find a sensible place to mention them, it wouldn't be a bad idea. -- Xerxes 15:33, 2005 Jun 2 (UTC)

They aren't hypothetical? It says they are hypothetical in both Webster's Dictionary and my school chemistry book. → JarlaxleArtemis 02:04, Jun 3, 2005 (UTC)

Ah… perhaps the correct term is theoretical. → JarlaxleArtemis 00:59, Jun 8, 2005 (UTC)

Yeah, just like electrons and evolution. -- Xerxes 17:48, 2005 Jun 8 (UTC)

Added to See also list.--Army1987 12:16, 16 August 2005 (UTC)

[edit] Top Quark Mass

Improved top quark mass measurements are finally coming out of the tevatron experiments. I've replaced the old run I "world average" of 178+/-4.3 GeV with the current best measurement from CDF run II of 173.5+/-4.1 GeV. A new "world average" taking into account Run II measurements should be available by the end of June 2005.

Thanks! Your research is very much appreciated. ‡ Jarlaxle 07:34, Jun 24, 2005 (UTC)

[edit] Fascinated, and totally lost.

I wish for the life of me that I could understand this subject. I enjoy physics on a hobbiest level immensely and love the books written by Bill Bryson, and Hawking, but for the life of me, it doesn't matter how many times or how many sources I read, I just go cross eyed when I see it. I simply cannot comprehend the principals involved.

Where exactly do you get lost? -- Rmrfstar 13:16, 3 December 2005 (UTC)

[edit] The spelling 'colour' should never be used for quarks

It's interesting that Nature didn't spot this but they may have thought it was British spelling. I clearly remember my quantum mechanics lecturers at the University of London saying that 'color' was an international standard when referring to quarks. Any objections to exclusive use of 'color'?

However the Encyclopædia Britannica seems to use the 'ou' version. I wonder about British physics journals. Glennh70

Everybody I know uses color, but if you switch it, Anglophiles will always come along and change it to colour. So I say, take the easy road and use colour to start out with. -- Xerxes 04:22, 16 December 2005 (UTC)

European journals use "colour" as do books, preprints, talks etc. written by most non-Americans. I think your lecturer was either pulling your leg or was American and couldn't be bothered to correct his slides. Besides if there were an international standard it would most likely be "colour" since that is the spelling in international (UN) English. (unsigned)

Actually, Nature uses British spelling exclusively because the editorial office is based in London. I've never heard or read that colour should not be used when it comes to describing quarks. I guess the lecturer didn't know what he was talking about or was just making fun. In European physics journals you'll often read colour. Nobbie 21:27, 27 January 2006 (UTC)

Yes colour is widely used in Europe, for example in the computer programme COLOUR, used to calculate QCD colour factors. I think both spellings are valid and shouldn't be corrected (Wikipedia policy is to leave whatever spelling was used when the article was written I think)137.138.46.155 09:16, 21 August 2006 (UTC)

[edit] Picture...

It would be nice to have some picture. Any thoughts? Or, better, pictures?--Piotr Konieczny aka Prokonsul Piotrus ^Talk 05:01, 16 December 2005 (UTC)

http://www.aip.org/png/images/quark-spin-png.jpg

This is a simple image that represents my idea of quarks quite well, it may be copyright protected though. Glennh70

Nice find. Maybe you can try Wikipedia:Boilerplate request for permission and ask for the author to licence the image under some nice copyleft licence? Quite often people agree to this.--Piotr Konieczny aka Prokonsul Piotrus ^Talk 19:21, 16 December 2005 (UTC)

[edit] Question on quark composition

I just happen to have a question: There has to be something smaller than the composition of a quark. Is there a smallest particle?

We don't know of any internal structure of quarks, at least not yet. We don't even have any evidence that they're larger than a single point. I'm not sure that there has to be a smaller particle, but it's one of the things particle physicists keep looking for. -- SCZenz 23:53, 17 December 2005 (UTC)

I would add that the assumption that there has to be something smaller is perhaps mistaken as SCZenz alluded to. Thinking of everything as being made of something else is rather classical in terms of physics. The composition of a quark is more of a quantum physics question, your whole philosophy of what existence is gets called into question at that level. Glennh70

The fact that a quark has a property, means it can be said to be made up of its properties. What causes a quark to have its properties would in theory reveal what subparticles a quark is composed of. However, if a force is a non-physical phenomena (a force outside the realm of what we call the physical world), then that force is technically not measurable using techniques bound by the laws of physics. We currently lack the instruments to measure certain things because either we cannot measure the supernatural, or there are things which have yet to be defined as natural (forces).

Um, what? As far as physicists are concerned, a quark could be a point particle with its own properties and no "pieces". A property need not correspond to a subparticle; all particles have several properties, e.g. a particular spin and a particular charge. -- SCZenz 17:25, 23 March 2006 (UTC)

Quarks are point particles in the standard model and although this can never be 100% proved it is widely accepted and not the source of much effort to confirm it.Jameskeates 09:19, 21 August 2006 (UTC)

I think String Theory might be able to explain this at some point in the future. Shvender Hoot 01:44, 05 January 2007 (EST)

[edit] Issue of Math With Physics

Exatcly. You really told me off there!:-) It's me again with another question: Some people think of elementary particles as geometrical points. However, points can be of indefinite size. They have no mass. All matter has mass, so there's mass made with no mass! I just want to know: If there is any particle that is the smallest there is, then there has to be something pre-existent for that particle to exist. It's a very hard concept to capture:almost like an existentialismistic paradox! I'm only 12 years old. Don't criticize, please!

Mass is actually a very difficult problem in particle physics. Quarks do have mass, although most of the mass from ordinary matter comes from the binding energy between quarks in a proton or neutron. Physicists actually don't believe that quarks (or other standard model particles) inherently have mass—it turns out it would screw up some fundamental symmetries of quantum field theory—rather, they believe that mass is given to them through something called the Higgs mechanism. I don't know if all that answers your question or makes things worse. ;-) -- SCZenz 00:01, 28 December 2005 (UTC)

By the way, you can usually get questions answered faster at Wikipedia:Reference desk/Science than at talk pages like this. -- SCZenz 00:02, 28 December 2005 (UTC)

Another comment: "mass made from no mass" is actually very possible. Particle masses can arise in several different ways from massless or nearly-massless particles; I alluded to two of them above. It's weird, isn't it? -- SCZenz 00:04, 28 December 2005 (UTC)

[edit] Yes,Me Again!

The reference section didn't help much, to my surprise!

Gluons contain supposedly the strongest binding energy in the universe. They hold together quarks, which hold together protons, neutrons, muons, etc., which hold together atoms, and so on. Now, here is my question: can this process be reversed; as in, is a small particle is made of an even smaller one, on a continually smaller scale? However, I cannot show this in a formula.--Not a User, but still smart

Why don't you skip the formula, since it doesn't make sense in TeX or non-TeX and just try to pose a question that is parseable. In "can there always be something made of something else in both ways?", please explain: What is "something"? What is "something else"? And what are the two ways in "both ways"? Then I can work on an answer. -- Xerxes 19:43, 28 December 2005 (UTC)

Sorry for the complexities! Well, all I can say is that the "something" could be anything - any object that you might think of. Even a dust particle, for instance. The dust particle, in theory, is made up of, or rather is, a group of molecules. these molecules are made up of atoms. The atoms are made of subatomic particles, whereas those are made of quarks. Then, if we could get any smaller, what would it be? For all we know, for the past 2050 years, this whole universe could be a simple part of a very large object! We have never explored this unimaginable vast space, so we cannot be certain of which type world we are in. By the way the 2 ways are a scale of large and small [particle size], such as 20 to the 100 billionth power, or 35 to the negative billionth power. It really doesn't matter what estimate we make; that segment of particle physics has been only semi-developed.--Not a User, but still smart

[edit] WP:FAC

It was suggested here that some of the articles revied by Nature could become Wikipedia:Featured articles. This one had no errors, and is quite good - anyone up for it? I think this one will need a decent copyedit first but otherwise looks quite good. -- ALoan (Talk) 12:11, 20 January 2006 (UTC)

[edit] Information on the naming of Quarks

I think some information regarding who, what, when, where, and why of quark naming should be included in this article. For example, why do they have uncommonly simple terms for their names, instead of some proper scientific name or some attributed name of some party or individual involved in their discovery? Or the reasoning behind the abstract terms chosen for names? I have no expertise in any field close to this, and I'm not exactly looking for an answer, it's just I think it's just something that could be included if information exists.

129.115.26.47 00:26, 7 February 2006 (UTC)

Basically, it's because we can name them anything we like, and this is funnier. I know offhand why some of them have the names we do (it's actually because they're the names of properties that were discovered earlier than the invention of the quark model). But anyway, yes the info should be included, and I'll add it to my list of things to look up and source properly. -- SCZenz 17:20, 23 March 2006 (UTC)

[edit] Colour/Color and Flavour

Can any of the quark flavours be any colour? Or does each flavour have a colour? Maybe I missed it somewhere in the article or discussion, but I still don't know!

Color and flavour are independent degrees of freedom. Any flavour may have any color. There are special cases called colour-flavour-locked superconductors, where each flavour in u,d,s does carry a separate colour. This sort of thing only happens at extremely high densities such as found in the core of a neutron star. -- Xerxes 16:34, 12 May 2006 (UTC)

[edit] quantum numbers

In the confinement and quark properties, it gives mass as an example of a quantum number. This surprised me, it doesn't fit nicely with obvious quantum numbers like spin. Perhaps someone with expert knowledge could explain what mass is a quantum number for to me, (or edit the article)? LeBofSportif 00:24, 12 May 2006 (UTC)

You are right; the sentence is wrong. I've corrected the wording. -- Xerxes 16:34, 12 May 2006 (UTC)

Ok thanks. LeBofSportif 19:34, 12 May 2006 (UTC)

[edit] Naming

The Finnegans Wake page says not from there. Citation one way or the other ? -- Beardo 14:02, 14 June 2006 (UTC)

I've definitely heard that assertion before. I'll look into it. -- SCZenz 14:28, 14 June 2006 (UTC)

He cited the book in the original paper: Physics Letters, Volume 8, Issue 3, 1 February 1964, Pages 214-215 (in note 6). See also [1] this page, or the OED entry for "quark". -- SCZenz 14:36, 14 June 2006 (UTC)

[edit] Whaddaya mean, too fast?

Near the beginning, it is stated that quarks are not seen, except for top quarks, which decay too fast. What does this mean? Too fast for the author's taste? If that's the case, this is a subjective opinion, contrary to NPOV. On the other hand, if it means they decay too fast to be seen, then the sentence as written makes no sense - ie, the top quark is NOT an exception, but just another invisible quark.

Hey there. Thanks so much for pointing out the sentence in question was unclear; I've rewritten it. In the future, could you ask for clarification a bit more politely and give the article authors the benefit of the doubt? -- SCZenz 22:59, 30 June 2006 (UTC)

in otherwords it decays too fast to be invisible 24.70.95.203 23:15, 16 July 2006 (UTC)

It decays too fast to have its properties obscured by hadronization. -- SCZenz 04:39, 17 July 2006 (UTC)

While no quark is ever observed alone (colour confinement) all other quarks can form hadrons (e.g. B mesons or charmonium) however top quarks never form bound states as they decay before this can happen. They are therefore inferred from their decay products, whereas others are said to be dircetly seen as composite particles containing them can be directly observed. Jameskeates 09:23, 21 August 2006 (UTC)

[edit] Structure

I've heard somewhere that nobody has been able to find if quakrs maintain any true structure, can someone verify this?

Here's the quote:

Why… do we think that electrons and quarks are the true ‘Greek atoms’…? [I]nvestigators have tried by many means to determine whether electrons, quarks… and gluons show any evidence of structure, and they have not found any. These experiments probed perhaps 10,000 times further than it took to see structure in the past, but electrons and quarks continue to behave as point-like objects with no parts.

[edit] An important property of quarks

The following statement, from the introduction, is internally inconsistent. If confinement is a property of quarks, there can't be an exception for one flavour. Would someone like to re-phase please? I believe we can simply get rid of the parenthetical clause; what it says may be true enough, but that's still not an exception. Do other editors agree? --MichaelMaggs 12:48, 14 August 2006 (UTC)

An important property of quarks is called confinement, which states that individual quarks are not seen because they are always confined inside subatomic particles called hadrons (e.g. protons and neutrons) (An exception is the top quark, which decays so quickly that it does not hadronize, and can therefore be observed more directly via its decay products).

[edit] Power generation?

In many of the more esoteric soft sci-fi universes Quarks are used to generate power. I don't know if this is even possible, but perhaps a section about Quarks in fiction should be added? I know I, personally, would love to find out if it is even possible.

Our style in physics articles is to keep the article to known facts or current scientific research on the topic. If there are interesting sources on quarks on fiction, you could write a separate article on that and link to it from here. As for power generation, as far as we know quarks aren't good for that; we can't figure out how to split them apart without putting in vast quantities of energy. -- SCZenz 19:44, 17 September 2006 (UTC)

[edit] My revert

I realize, upon reflection, that I shouldn't have used the administrative anti-vandalism rollback button to remove the statement that the term "qaurk" is of German origin. Although this is factually incorrect (the article cites the original paper on quarks, which states that the source is, in fact, Finnegans Wake), it appears to have been a good-faith edit and I should have reverted normally. -- SCZenz 19:42, 17 September 2006 (UTC)

[edit] Joke theory

What is Quark? Quark is the name of a tart, unripened cheese from central Europe that is virtually identical to Fromage Blanc or in New Orleans, what we call Creole Cream Cheese, but with a slightly higher fat content. The word "quark" is German for "curds" and has also been used as a figure of speech for "nonsense."

I guess those would be different uses of the same word. If you want, you could write articles on that stuff too, under names like Quark (cheese) or whatever. -- SCZenz 20:07, 17 September 2006 (UTC)

Also, can you please sign your talk page comments by using four tildes, like this: ~~~~ -- SCZenz 20:08, 17 September 2006 (UTC)

[edit] Masses

Why are only the MS-bar masses given in the article? Also, its certainly not the case that the top quark mass listed comes from any sort of MS-bar calculation. Bodhitha 19:54, 21 September 2006 (UTC)

How different are the masses given by other types of calculations? Will anyone come to this article expecting to find such detailed information? I don't think we're trying to replace the PDG here. You're right about the top, though—I'll make sure that's clear. -- SCZenz 20:26, 21 September 2006 (UTC)

You're right-- they're not very different for the light quarks. I'm not so sure about the b quark though. I'm no expert on how these calculations are done, but I know for many experimental analyses, the "pole mass" (4.7 GeV) is used, and not the MS-bar calculations (which are lighter). Bodhitha 20:25, 24 September 2006 (UTC)

[edit] GA Re-Review and In-line citations

Members of the Wikipedia:WikiProject Good articles are in the process of doing a re-review of current Good Article listings to ensure compliance with the standards of the Good Article Criteria. (Discussion of the changes and re-review can be found here). A significant change to the GA criteria is the mandatory use of some sort of in-line citation (In accordance to WP:CITE) to be used in order for an article to pass the verification and reference criteria. Currently this article does not include in-line citations. It is recommended that the article's editors take a look at the inclusion of in-line citations as well as how the article stacks up against the rest of the Good Article criteria. GA reviewers will give you at least a week's time from the date of this notice to work on the in-line citations before doing a full re-review and deciding if the article still merits being considered a Good Article or would need to be de-listed. If you have any questions, please don't hesitate to contact us on the Good Article project talk page or you may contact me personally. On behalf of the Good Articles Project, I want to thank you for all the time and effort that you have put into working on this article and improving the overall quality of the Wikipedia project. Agne 00:13, 26 September 2006 (UTC)

[edit] Experimental results of quark charges

I was reading this article and I wonder if someone here knows if any experiments can verify the electric charges of the quarks, e.g. that an up-quark has the charge +(2/3)e, and a down-quark -(1/3)e? Actually I have been pondering upon this for many years; to me it sometimes sounds a little bit too simple/convenient that the charges are made up of thirds (please forgive me, as I am not an expert on quark theory). But I'd really like to know about empirical experiments regarding this, and the precision (+/-) in such measurements. My regards, --Dna-Dennis ^{talk - contribs} 04:00, 4 October 2006 (UTC)

I'd have to look up deep inelastic scattering experiments and see what kinds of fits they might have done, and what assumptions made, in directly measuring the quark charge. However, the following is well-known: a proton (charge e) contains two up quarks and a down, while a neutron (charge 0) contains one up quark and two downs. Thus we have:

2 q u + q d = e

q u + 2 q d = 0

The solution to these equations is precisely

q u = (2 / 3) e, q d = ( - 1 / 3) e

—so unless we're wrong about the constituents of protons and neutrons, these charges are not in doubt. It is certainly a great mystery of physics why the up and down quarks should have charges in units of thirds of the electron charge; this is the inspiration for Grand Unified Theories, for example. -- SCZenz 04:41, 4 October 2006 (UTC)

Since the top quark decays before hadronization, you can actually measure its charge "directly" (or rather, measure the charge of its immediate decay products). There are efforts underway to do this at the Tevatron experiments. Bodhitha 13:57, 4 October 2006 (UTC)

Thanks for your answer, SCZenz! Yes, I've naturally understood that the charge arrangement is a consequence of the quark model and is crucial to the theory, and that other arrangements would challenge it fundamentally. What I wonder is how well the results of empirical experiments regarding charges comply with the assumptions (I'm not challenging it, I'm just being nosy). Since it has been concluded that there are three points of electrical deflection in baryons, I wonder if the experiments have yielded any data regarding the magnitude of deflection, which can give us a hint regarding the constituent charges. If you have any links I would be very interested and thankful. And thanks Bodhitha, the upcoming experiments sounds very interesting, and same thing here, if you have any links it would be appreciated. Thanks again to both of you for your answers. Regards, --Dna-Dennis ^{talk - contribs} 15:15, 6 October 2006 (UTC)

[edit] Diagram needed

Please insert a diagram showing the relationship of the up, down, charmed, etc. properties of quarks. I know there was a good one up at he fermi lab site a long time ago, but I can't find it any more. -SharkD 17:44, 28 October 2006 (UTC)

Retrieved from "http://en.wikipedia.org../../../q/u/a/Talk%7EQuark_71d6.html"