Talk:Quark

Footnote about generations and neutrinos

Footnote 1 currently says

The main evidence is based on the resonance width of the Z0 boson, which constrains the 4th generation neutrino to have a mass greater than ~45 GeV/c². This would be highly contrasting with the other three generations' neutrinos, whose masses cannot exceed 2 MeV/c².

but as far as I can tell in the Standard Model there's no obvious reason why there should be as many generation of quarks as of leptons (though GUTs do predict that). Am I missing something? If not, I propose to remove that footnote as misleading. — A. di M.  18:29, 23 October 2018 (UTC)

Anomaly cancelation (TTY) in the standard model pegs the numbers of EW lepton doublets to those of quark doublets (acounting for color triplication). This is the very cornerstone of the SM generation structure. Is this what you might be missing? Cuzkatzimhut (talk) 19:02, 23 October 2018 (UTC)

How reliable is the Quark hypothesis?

First I would remaind you on the failure of the LHC-experiment at CERN. It was made to prove "Quarks" definitively.

Second: As we know were this particles predicted by theory. They have therefore merely theoretical need. It is questionable to declare the reality (in this case the world of particles and nuclei) by theoretical considerations. We have to be close to the experimental facts and observations.

Third it is possible to describe the world of particles and nuclei using the most elementary particles electron and positron. The world of particles is probably substantial differnt from the accepted theoretical description.

Some links:

https://www.researchgate.net/publication/301614262_The_Reason_of_a_realistic_View_to_Particles_and_Atomic_Nuclei?_sg=hdVJqrb66numVZAqlGaR7wxlIU3O419A59IZN6SIg5a8YFpSRRNRXNQq39vIoKaR-CixThpeoPn2dw.oloZG9HAv2x3YqOSTaOnLYKfe7IECdwDLd-hXeIiGSpUsT1bfduXO5Vh3IuNqhlArFxyIlWE7_-hblBXT_jsTg&_sgd%5Bnc%5D=0&_sgd%5Bncwor%5D=0

http://www.erkennbare-welt.de/Teilchen&Kerne

hg.hil2003:CE:ABC5:3FDB:888A:C133:AA37:8E4D (talk) 09:21, 11 March 2019 (UTC)

And I should remind you of the rule on the very second line of this page. Cuzkatzimhut (talk) 14:26, 11 March 2019 (UTC)

Video of Gell-Mann explaining the pronunciation and origin of the word quark

https://youtube.com/watch?v=po-SQ33Kn6U --Espoo (talk) 00:13, 30 May 2019 (UTC)

Free quark

This source clearly states that they're doing experiment with free quark, which exists in a state called quark-gluon plasma. Free quark means that it's no longer in confinement. Free quark = isolated quark. In color confinement, it clearly states that quark "cannot be isolated, and therefore cannot be directly observed in normal conditions below the Hagedorn temperature". It means that ABOVE the Hagedorn temperature, quark can be isolated and observed directly. Stop reverting my edits. You guys are probably amatuer in physics at best. Do you even know what I do for a living? I came across this article and saw a glaring error, so I decided to fix it.2402:800:436F:5C80:C9D4:EFF:4DC3:6B91 (talk) 02:39, 10 June 2020 (UTC)

Free has come to mean ‘’isolated’’ and quarks in plasma are not isolated. Please read up. Cuzkatzimhut (talk) 02:49, 10 June 2020 (UTC)

Quote from the source, "however, quarks and gluons were bound only weakly, free to move on their own in what’s called a quark-gluon plasma." This directly contradicts the statement you're trying to keep, "they can be found only within hadrons, which include baryons." Free and isolated mean the same thing in this case. It means that the quarks are no longer in confinement. You also conpletely ignored above the Hagedorn temperature part, which also proves my point.2402:800:436F:5C80:C9D4:EFF:4DC3:6B91 (talk) 02:59, 10 June 2020 (UTC)

Your knowledge of physics is really bad, no offense. First of all, this is not just any plasma, which is one of the four basic states of matter. There are many more states of matter than the basic four. This state of matter is called "quark-gluon plasma", which is not the same as your ordinary plasma state that you probably learned in high school. You should take a course or two in quantum mechanics to broaden your knowledge. Perhaps, take my course too. 2402:800:436F:5C80:C9D4:EFF:4DC3:6B91 (talk) 03:08, 10 June 2020 (UTC)

Quarks in plasma are not isolated. You are misreading the source you quote. They are weakly interacting. Please read something above a press release.Cuzkatzimhut (talk) 03:06, 10 June 2020 (UTC)

You keep misinterpreting my words based on your poor understanding of physics. They are weakly interacting, yes. But, they are also "free to move on their own". This MEANS that they are no longer in color confinement scheme. This contradicts directly the statement you're trying to keep, "they can be found only within hadrons, which include baryons."2402:800:436F:5C80:C9D4:EFF:4DC3:6B91 (talk) 03:13, 10 June 2020 (UTC)

There are also these jets occurring in the quark-gluon plasma. By measuring the "jets' orientation, directionality, composition, and how they transfer energy and momentum to the medium", you can observe the quarks directly. Do you even know how scientists observe an electron directly?2402:800:436F:5C80:C9D4:EFF:4DC3:6B91 (talk) 03:19, 10 June 2020 (UTC)

You also keep ignoring one of my key arguments, "ABOVE the Hagedorn temperature, quark can be isolated and observed directly." You actually need to read the Hagedorn temperature article on Wikipedia instead of ignoring my valid point.2402:800:436F:5C80:C9D4:EFF:4DC3:6B91 (talk) 03:25, 10 June 2020 (UTC)

Leave the lede alone. The final section addresses QGP without misleading flourishes. I first read Hagedorn’s paper in 1975; publishing in professional HEP literature since. You need to read up. This is not a forum. Cuzkatzimhut (talk) 10:52, 10 June 2020 (UTC)

I cited my source. This is not a forum to espouse your poor understanding of physics. If you actually read Hagedorn's paper in 1975, you should reread it now (I doubt you did). It's 2020 now, 45 years has since passed. Also, I highly doubt you've published anything in HEP literature due to your poor understanding of particle physics.

This statement is clearly scientific incorrect: "Due to a phenomenon known as color confinement, quarks are never directly observed or found in isolation; they can be found only within hadrons, which include baryons (such as protons and neutrons) and mesons (all of which are unstable and short-lived." This statement is incorrect and misleading. Just because QGP is addressed at the end, it doesn't mean we should leave a scientific incorrect statement in the opening section. Also, this article became a featured article in 2009, which means it hasn't been edited a lot for 11 years. A lot of things have changed since then within the physics community.

You literally have been ignoring every scientific fact I provided here and continue to revert my edit based on your poor, ignorant understanding of particle physics. So far, you have provided ZERO scientific fact to back up your claim. The idea that "quarks are always in color confinement" is outdated and needs to be updated as in with every single field in science. As scientists delve deeper into nature, things that we thought were true are no longer correct based on new experimental data. 14.169.172.125 (talk) 12:06, 10 June 2020 (UTC)

Quoted from another source, "If the conditions for forming a bound state aren't met, then confinement is impossible. The four ways we know how to get there are to create a top quark, to look to the early stages of the hot Big Bang, to collide heavy ions together at relativistic speeds, or to look inside the densest objects (like neutron stars or the hypothetical strange quark stars) to find the quark-gluon plasma inside." It clearly states there are four different ways to create free quarks, unbound from color confinement. 14.169.172.125 (talk) 12:18, 10 June 2020 (UTC)

Sigh... Isolated quarks means asymptotic states, and not "asymptotically free quarks", as you might well be misconstruing them. You must be confused about the meaning of asymptotic freedom. Please go to the Quark–gluon plasma page for clarification. This is not a forum. Cuzkatzimhut (talk) 12:33, 10 June 2020 (UTC)

When I said isolated quarks, I mean free quarks. The quarks are free from their color confinement. A quote, "This state is thought to consist of asymptotically free strong-interacting quarks and gluons, which are ordinarily confined by color confinement inside atomic nuclei or other hadrons" from the quark-gluon plasma article. Asymptotically free quarks = quarks that are no longer in color confinement. Please read Asymptotic freedom. Again, you repeatedly ignore my sources and my other points. You offer nothing to dispute my claim beside circular argument and some fancy words that you probably have 0 understanding. 14.169.172.125 (talk) 12:53, 10 June 2020 (UTC)

"I mean free quarks" may be at the root of your misconception. An asymptotic state is completely isolated from any other quarks or excitations, here, colored ones. QGP is a medium replete with color degrees of freedom. While you might split hairs in the suitable section or article, messing with the lede in an important article to service tendentious misunderstandings is simply not OK. Cuzkatzimhut (talk) 13:00, 10 June 2020 (UTC)

I didn't misunderstand anything. I fixed a fact about free quarks, and you reverted them without a deep understanding of particle physics. You ignored all my valid points and argued non-sense. Keeping a scientifically incorrect statement in the lede is not OK.

"An asymptotic state is completely isolated from any other quarks or excitations, here, colored ones." This statement is blatantly wrong. Asymptotic state is a state where quark and gluon are moving freely unbound by color confinement. Quark-gluon plasma IS an asymptotic state. Asymptotic free quarks are free particles for all intended purposes in science. Read up Asymptotic freedom.

"QGP is a medium replete with color degrees of freedom." This is just nonsense. Color in color refinement refers to particles that are color-charged namely quarks and gluons. QGP is when color-charged particles break free from their confinement. 14.169.172.125 (talk) 13:29, 10 June 2020 (UTC)

The more you talk the more it exposes that you REALLY don't know what you're talking about and lack a deep understanding of physics. You said, "free in a limit: they have to thermalize." Yes, it's a limit. Physicists use math to describe nature. It is simply a construct that helps us to explain nature better. Above the Hagedorn temperature, this limit is reached, and quarks act as free particles. I provide 3 sources that support this (there are many many more). Limit or math is just a construct. When you do the experiment, it shows that quarks act like free particle, so they are free by definition under the conditions of the experiment. And, it doesn't matter if they have to thermalize to be free (in the end, they are still free particles). Your argument is moot at this point. "They can be found only within hadrons" claim is simply WRONG. That's what we thought many decades ago, but now that idea has been discarded through repeated experiments around the world.14.169.212.232 (talk) 04:49, 11 June 2020 (UTC)

Please, do not attack other editors otherwise your editing privileges may be withdrawn. Ruslik_Zero 05:51, 11 June 2020 (UTC)

• I am not sure I understand what is being discussed. I hope nobody here denies that whereas at the ambient conditions quarks are bound (by gluons) into baryons and mesons, at high energy baryons and mesons become quark-gluon plasma, and for example this is what was believed to during the Big Bang. I am not familiar with the details of this CERN experiment (and I would have preferred to have a look at the paper if it is out), but it is just a matter of writing this in a semantically correct way.--Ymblanter (talk) 10:41, 11 June 2020 (UTC)

  There is actually a section on quark-gluon plasma already in the article. May be indeed adding a sentence to the lede would be beneficial?--Ymblanter (talk) 10:43, 11 June 2020 (UTC)

  Ymblanter yes, please. Because claiming quarks "can be found only within hadrons" is simply just scientifically incorrect because they're obviously found outside of hadrons (such as in quark-gluon plasma). Also, claiming quarks can never exist outside of color confinement is also incorrect (equivalent of saying quarks can never be found in isolation -> incorrect). Quarks found in isolation means free quarks unbound by color confinement, which happens in the quark-gluon plasma.

  Please take a look at my edit before it was reverted (I added 3 reliable sources). That was my proposal to clarify the nature of quarks to be more scientifically correct. 14.169.212.232 (talk) 10:58, 11 June 2020 (UTC)

The footnote nb1 adducing QGP is still there!Cuzkatzimhut (talk) 11:19, 11 June 2020 (UTC)

Cuzkatzimhut, User:Ymblanter fine, I would no longer object to it if "below the Hagedorn temperature" is added after the word isolation. And the word only is deleted from "they can be found only within hadrons." You can't use the word only when that is not the only place that you find quarks! Thank you all for the help. 14.169.212.232 (talk) 11:38, 11 June 2020 (UTC)

Also, the top quark has been observed DIRECTLY. Therefore, claiming quarks can never be observed directly is simply false. Like I said the information in the lede is outdated. It needs to be updated as physicists dig deeper into nature. 14.169.212.232 (talk) 11:52, 11 June 2020 (UTC)

You are (again) misreading the sentences "Quarks carry color charge and cannot be observed directly as they hadronize to colorless particles before decaying. One exception is the top quark, as it decays before hadronization due to its short lifetime. " The exception is not to the directness, but to the hadronization, obviously. Most observations in HEP are indirect, but this one takes the prize. Cuzkatzimhut (talk) 13:09, 11 June 2020 (UTC)

I didn't misread anything. You're just stating the definition of color confinement without proving anything. You admit there is an exception yes? If there is an exception then saying quarks can never be observed directly is clearly a false statement. Not sure what you mean by, "The exception is not to the directness, but to the hadronization." You're just arguing for the sake of argument at this point. Exception is exception, period. It's just a fact that a top quark has been observed directly; this fact refutes your statement in the article. A top quark IS a quark.

And the claim quarks can only be found within hadrons is incorrect that hasn't been fixed. The word "only" needs to be deleted. And, quarks have been found in isolation, which means it's no longer bound by color confinement. 14.169.212.232 (talk) 13:23, 11 June 2020 (UTC)

Sigh... The exception is in that the top decays before it hadronizes, so it cannot fail to be detected directly because of hadronization! That is, it has disappeared at a distance scale shorter than the size of the hadron in which it would be included, and certainly that of its decay products, b, etc. It has spent its entire life in the hadronic fireball in which it was created, of size smaller than a fermi, and certainly it has not "beaten confinement" in this blob! Cuzkatzimhut (talk) 13:52, 11 June 2020 (UTC)

I understand your point. However, I can argue the same opposite thing. Hadronization fails because the top quark decays quicker than the time it takes to hadronize. Exception is an exception. There is no way to get around it. Claiming all quarks can never be observed directly is simply false. 14.169.212.232 (talk) 14:48, 11 June 2020 (UTC)

No, your are, in fact, arguing for the same thing! You observe the t indirectly, in the same way you are observing the s quark in a K decaying to pions, or the c quark in Ds. The authors never intended anyone to understand the decay of the t is not conventional, and indirect. You are investing "directly" with an eccentric meaning never intended. c (talk) 15:46, 11 June 2020 (UTC)

"The authors never intended anyone to understand the decay of the t is not conventional, and indirect." This sounds like your own original research (they didn't say it; you synthesized it out of thin air). No original research please, according to Wikipedia policy. And no, it's not the same thing. Top quark spin's effect is measurable. It's the same way when we observe a photon emitted from an electron. That's a direct observation of the electron. That's as direct as you can get in particle physics.

Other physicists around the world agree with me, not you. They take the result and say that's direct observation of the top quark. source 1 (a published book in particle physics), source 2 (another published book in particle physics). You need to start providing reliable sources to back up your claim, of which I haven't seen a single reliable source provided by you, and stop making up stuffs (or espousing your own original research). I, on the other hands, have provided A LOT of reliable sources (there are a lot more on the internet; I just picked a few of them). 14.169.212.232 (talk) 18:16, 11 June 2020 (UTC)

I generally agree with Cuzkatzimhut here. The current version of the opening paragraph seems satisfactory to me, hitting the appropriate level of detail and covering the basic facts, bringing in baryons, mesons and QGP at the appropriate point. The discussion is also ongoing at Wikipedia_talk:WikiProject_Physics#Quark_dispute. XOR'easter (talk) 18:11, 11 June 2020 (UTC)

Appropriation is not the same as scientifically correct. 14.169.212.232 (talk) 18:49, 11 June 2020 (UTC)

To the extent that it needs repeating, Gell-Mann was diffident about quarks for 10 years, because of the (ultimately 30-year long) failure of isolated fractionally-charged particles' searches to bear fruit. This is the first feature a physics student or a layman should see about quarks, happening nowhere else in physics. Hitting them right away with qualifications, hair-splittings, and notional prestidigitations detracts from the central key point. There is plenty of room for finessing Hagedorn temps and their more usable analogs (!) later in the article, and in the penumbral technical articles linked. The key point is to not puzzle and confuse the eager novice with "ifs" and "but"s. Cuzkatzimhut (talk) 19:01, 11 June 2020 (UTC)

Who said Wikipedia is written for a layman (it's Simple English Wikipedia job)? Also, it's imperative for a physics student to learn the correct thing right away. So later on, they don't have to go through the "wait, what!" moment. Fact is fact. They'll just have to deal with it.

Fine, keep your "only". However, "below the Hagedorn temperature" needs to be added, and "directly observed or" needs to be deleted. I don't think adding 4 words and deleting 3 words to the article is "hitting them right away with qualifications, hair-splittings, and notional prestidigitations." It won't hurt to add 4 words into the article. Deal? I'm ready to move on from Wikipedia editing and go back to my daily routine. It's basically the same statement taken from color confinement. 2402:800:4368:7FA6:DC73:9475:FC7F:1743 (talk) 19:30, 11 June 2020 (UTC)

Above the Hagedorn temperature, quarks break out of hadronic bound states and propagate as quasi-free excitations in an extended colored medium, not in the vacuum: they may not be said to be isolated. One infers their properties, not too differently than inferring the scattered quark properties from the features of a hadronic QCD jet. The statement of the color confinement article is muddy and misleading, in my view, but I have no experience with that page--it certainly didn't come out of Barger and Phillips cited! I believe it should be improved, but the novice hardly stumbles there. Cuzkatzimhut (talk) 20:10, 11 June 2020 (UTC)

Theoretically, free quarks can be observed directly in the quark-gluon plasma. They haven't been successful on that, but they're working on it. I know they're working on it because I read it in a source somewhere. The current problem is that they cannot sustain the quark-gluon plasma state for very long to observe free quarks directly. Maybe, in a few years? The Large Hadron Collider is constantly being upgraded. Anyway, this is beside the point being discussed. Top quark alone proves that claiming all quarks are never directly observed is not true.

Free quarks or isolated quarks mean the same thing in this case. It means they are free from color confinement. It doesn't matter if they're in the vacuum or in the quark-gluon plasma. The result is the same; they are free or isolated from color confinement. This interpretation of free quarks (isolated quarks) is supported by CERN and Nature journal (and other sources). 2402:800:4368:7FA6:DC73:9475:FC7F:1743 (talk) 20:26, 11 June 2020 (UTC)

The two sources that support this statement, "color-charged particles (such as quarks and gluons) cannot be isolated, and therefore cannot be directly observed in normal conditions below the Hagedorn temperature" from color confinement seem reliable to me. 1 is from a published book, second one is from published lecture notes. It's as legit as Feynman lecture notes. 2402:800:4368:7FA6:DC73:9475:FC7F:1743 (talk) 20:34, 11 June 2020 (UTC)

Where is your reliable source saying it has to be in the vacuum for it to be considered free (or isolated)? If you can't provide a reliable source, your argument would be invalid. No original research please and no original interpretation. 2402:800:4368:7FA6:DC73:9475:FC7F:1743 (talk) 20:41, 11 June 2020 (UTC)

A free quark in Gell-Mann's, Zweig's, and Feynman's usage (no sources: I worked for them), and everybody else's (indeed), is an isolated quark coming from outer space, or hovering in space, or hitting a detector which thereby registers fractional charge, so, not hadronized; these were searched for for decades, unsuccessfully. They don't exist for a reason. QGP is normally a blob of no more than a few fermis wide, produced by the collision of hadrons or nuclei, and so, could be thought of as an extreme bag of colored entities. The fact that quarks propagate "freely" in it is hardly different, conceptually, than partons in a hadron struck at extreme $Q^{2}$s, so a huge contrast. That's just why the "free" terminology is deprecated in favor of "isolated". I'd be flattered to consider any of this as original research or interpretations! Cuzkatzimhut (talk) 21:06, 11 June 2020 (UTC)

I still believe isolation in this case means isolated or free from color confinement (all my sources have different interpretation of free quarks than yours). However, if you really want to keep your argument of isolated as in the vacuum then for better clarification, I suggest adding "in the vacuum" after "found in isolation". Or you can say "quarks can never be isolated in the vacuum." 14.169.100.161 (talk) 05:35, 12 June 2020 (UTC)

You are chasing a red herring by looking for the "correct" technical meaning of "in isolation". This is the lede of a highly visible Wikipedia article. Therefore it is written in non-technical language, as far as possible. "In isolation" here is used in the "lay" English sense of "far removed other things". Quark-gluon plasmas and particle decays in a collider, do not fall in this common understanding of "isolated". TR 12:02, 12 June 2020 (UTC)

Then you need to say, "quarks can never be isolated in the vacuum" to make it a scientific correct statement. Wikipedia serves not only the layman but also the experts in particle physics. A little clarification can't ever hurt. 2402:800:4329:851A:B1B5:E074:25A3:4DC5 (talk) 13:24, 12 June 2020 (UTC)

That would be more problematic as there is no such thing as "the vacuum". An important aspect of writing an accessible lede is being sufficiently imprecise as to still be accurate (but not more so). (Also nice double negative.) TR 14:16, 12 June 2020 (UTC)

There is, but yea, it can never be completely empty due to quantum fluctuation, dark matter, dark energy, and maybe more things that we just don't know yet. It depends on your definition of the vacuum, which would lead to another rabbit hole. In any case, most of my concerns have been addressed thanks mostly to your edits. I'm not completely satisfied with this last bit but, but I guess that's life (can't have everything my way). It's time we say farewell to each other. 14.169.171.239 (talk) 17:20, 12 June 2020 (UTC)

Quark structure of nuclei, e.g. deuteron having large quadrupole moment?

What happens with quark structure e.g. of proton + neutron when they bind into deuteron?

We know it has large electric quadrupole moment ( https://en.wikipedia.org/wiki/Deuterium#Magnetic_and_electric_multipoles ), what seems tough to get if thinking about it as just 'pn' (?)

It is explained by adding l=2 angular momentum, but it suggests some dynamics - what exactly?

Couldn't this quadrupole be obtained by just shifting some quarks instead? (I got such suggestion from soliton particle models) Jarek Duda (talk) 07:07, 19 June 2020 (UTC)

Not a forum. Cuzkatzimhut (talk) 10:01, 19 June 2020 (UTC)

If quarks build nucleons, which build nuclei of all atoms around us ... isn't the role of quarks in nuclei a basic question - which should addressed in their Wikipedia article? Jarek Duda (talk) 10:17, 19 June 2020 (UTC)

It might be an interesting question, if and when a good answer were at hand. WP summarizes clear results, and does not blithely rush to the muddiest of conceptual corners. Cuzkatzimhut (talk) 15:35, 19 June 2020 (UTC)

Attribution of discovery

It seems odd to attribute the discovery of quarks to SLAC without any mention of the Nobel Prize awarded for that work to Friedman, Kendall, and Taylor. Surely it merits a sentence. 174.62.81.41 (talk) 03:05, 10 March 2023 (UTC)

I added a sentence. --mfb (talk) 07:59, 10 March 2023 (UTC)