# Talk:Charm quark

Could somebody make an attempt to introduce this material to non-scientists?

I don't understand your issue. The article only says the quark properties (charge, mass,..), who predicted it, who discovered it, and some examples of particles that contain the charm quark. If anyone seeks to understand what a quark is should go to the quark page. Maybe the J/Psi explanation is a bit messy, but i don't find any other problem.
I agree. All the quark articles are like this. Tag removed. Anonimu 01:15, 19 April 2007 (UTC)
Yes, it needs an introductory paragraph geared down to laypeople. The first sentence is lay-unintelligible; a linked term therein (generation) leads down a rabbit hole leading to another rabbit hole (flavor quantum number). I remember Richard Feynman lamenting the abrupt shift from traditional Encyclopedia Britannica to the modern format: in the old you could follow an article from beginning to end.
But it is endemic to the writing of Wikipedia articles these days; specialists and topic-fans writing for other specialists and topic-fans, who have lost all pedagogical bearings as to the purpose of encyclopedic presentations. JohndanR (talk) 15:52, 26 December 2023 (UTC)
I agree that Wikipedia should strive for more accessible articles. I reworked the intro.
One issue in making articles more accessible is to understand what people understand. If you read Feynman's QED: The Strange Theory of Light and Matter and other works you will see he often just gives up because the step is simply too big. What could we possible write here that would help?
However, I think the real issue here is the topic. This thing is simply not very important beyond expert and specialists. It's not practical nor desirable to have an entirely accessible article on this topic. Johnjbarton (talk) 17:36, 26 December 2023 (UTC)

Was the charm originally called charity? Regardless, where did the name come from? And why is there some discussion of the naming of some other particle instead, that's just confusing (ie. belongs elsewhere), plus there's that equation with no explanation (any idea what it means?)...  —Preceding unsigned comment added by 150.203.48.127 (talk) 05:47, 20 November 2007 (UTC) 

In the Quark article it states that: *

Sheldon Lee Glashow and James Bjorken, predicted the existence of a fourth flavor of quark, which they referred to as charm (c). This would have been around 1965. 

The article also states that:

In a 1970 paper,[16] Glashow, John Iliopoulos, and Luciano Maiani gave more compelling theoretical arguments for the as-yet undiscovered charm quark.

This Charm article states that 

The charm quark [...] was predicted in 1970 by Sheldon Glashow, John Iliopoulos, and Luciano Maiani, and first observed in November 1974

and

The quark itself derived its name from the "charmed" life the J/ψ leads, having a half-life a thousand times longer than had been predicted theoretically.

The contradictions, predicted in 1965 vs. in 1970 and named in 1965 when proposed vs. named in 1974 after an experimental discovery, need to be fixed. 78.147.26.143 (talk) 18:02, 5 October 2008 (UTC)

Actually as of today, the Quark article says: "Glashow, who coproposed charm quark with Bjorken, is quoted as saying, "We called our construct the 'charmed quark', for we were fascinated and pleased by the symmetry it brought to the subnuclear world"; and an original source is given.  Why are all references in this article refer to it as "charm" rather than "charmed"?  This conveys a different meaning and calls for explanation.  (The same confusion appears in many other places.)  SteveG23 (talk) 14:17, 28 November 2009 (UTC)

This says they were theorized by Glashow Illious and Maini in 1970. Quark says they were theorized by Glashow and Bjorken in 1964.Headbomb {ταλκκοντριβς – WP Physics} 02:28, 20 December 2008 (UTC)

According to the numbers on the current image for the particles of the standard model, charm quarks are the third most massive quarks, behind bottom and top (top being the most massive). Up and down and clearly stated to be the smallest, and strange is listed at 104 MeV, which is smaller than charm's 1.27 GeV. I'm guessing this discrepancy has to do with the "/c^2" in the statistic making charm fourth, but I don't see how the speed of light would have that small an effect on the resulting number (1.27e9 -> 1.5e9). ~XarBioGeek (talk) 05:46, 18 October 2009 (UTC)

No, it was due to me wanting to say it came 4th if you listed quarks from lightest to heaviest. Somehow that came out as '4th most massive'. MeV are MeV/c^2 equivalent (the former uses the convention that c = 1). Headbomb {ταλκκοντριβς – WP Physics} 14:34, 18 October 2009 (UTC)
And now (well, last month) it's been changed back to "fourth most massive". I assume this is a simple mistake similar to the above, but don't want to revert it myself on the off chance that the topic is more complicated than I think it is. Emurphy42 (talk) 03:23, 11 April 2014 (UTC)

if some one can get a hold of C. T. H. Davies, C. McNeile, K. Y. Wong, E. Follana, R. Horgan, K. Hornbostel, G. P. Lepage, J. Shigemitsu, H. Trottier. Precise Charm to Strange Mass Ratio and Light Quark Masses from Full Lattice QCD. Physical Review Letters, 2010; 104 (13): 132003 DOI: 10.1103/PhysRevLett.104.132003 it is purported to have refined values for qs and qc 
Abyssoft (talk) 04:49, 24 May 2010 (UTC)
2010 PDG values have been posted, http://pdg.lbl.gov/2010/2010/tables/rpp2010-sum-quarks.pdf
I will wait a few more days before making the changes to mass. If there are no objections I'll apply the changes on Friday August 06, 2010 sometime between 0700 and 2200 UTC.
Abyssoft (talk) 20:29, 2 August 2010 (UTC)

Given that from the data mc is 1.27+0.07−0.11 GeV/c2 and mb is 4.20+0.17−0.07 GeV/c2 by (MS scheme) and 4.68+0.17−0.07 GeV/c2 (1S scheme)
then mb-mc as currently stated by PDG source of 3.43+0.05−0.05 GeV/c2 is above the mathematically evaluated mb-mc where (MS scheme) is used for mb (3.00+0.21−0.21 GeV/c2), and is completely interior to mb-mc where (1S scheme) is used for mb (3.48+0.21−0.21 GeV/c2); therefore can it not be adequately assumed that the values derived by use of the (MS scheme) are outside acceptable range and should thus be removed or noted as such.
Abyssoft (talk) 17:37, 16 June 2010 (UTC)
You cannot just add or subtract masses given for different particles, as given in the PDG. The listed masses are the values of the running masses evaluated at a reference energy equal to the relevant quark mass. To calculate the difference of bottom and charm masses, just specify at what reference energy you want to compare the masses and adjust the masses to that level.TimothyRias (talk) 12:33, 17 June 2010 (UTC)
Even though it would be technically "OR", could you provide the maths needed to do this it sounds interesting Timothy? 64.27.60.18 (talk) 23:50, 17 June 2010 (UTC)

There was a somewhat recent edit that changed the decay particle "up quark" to "down quark". I did a quick search and couldn't find something that clearly said one or the other in terms that I, having no background in particle physics whatsoever, could understand (just one about charm decaying into strange). TimothyRias added a source for charms decaying into downs (thank you), but I looked at it and couldn't find a clear statement indicative of that.

Can charms decay into either up or down quarks? Can they decay into up or down antiquarks, as the source for decaying into strange seems to indicate?
Can someone (who understands such sources) find sources for those, and ideally add quotations from those sources that make it clear (simplifying the verification)?
Thanks. ~rezecib (talk) 20:40, 7 December 2010 (UTC)

Somehow I completely missed the sentence "The c quark has about 5% probability of decaying into a d quark instead of an s quark." in the hyperphysics source, which covers both nicely. I set that to the quote for the source. The other questions still remain, as the article did list "up quark" as a decay particle from 24 March 2010 to 5 December 2010, which makes it seem like it might've had at least some validity. ~rezecib (talk) 22:42, 7 December 2010 (UTC)
BTW, the "up quark" was a leftover from a copy-paste I made several months ago. It was my mistake, but somehow went unnoticed for ages. Headbomb {talk / contribs / physics / books} 00:38, 8 December 2010 (UTC)

I like the main picture. It's so CHARMing! Фин Рептилоид (talk) 20:36, 5 January 2021 (UTC)

It is stated  in This article. A secondary source is available here.  — Preceding unsigned comment added by 151.68.108.26 (talk) 16:34, 31 August 2022 (UTC) 

...that physicists betted on wine 
should read
that physicists bet a bottle of wine
But I think the ALT1 is better. Johnjbarton (talk) 20:50, 3 June 2023 (UTC)
Hi User:Johnjbarton,
Nominator here. Unfortunately the phrase "bet a bottle of wine" deviates from the fact that Iliopoulos bet "cases of wine". I will modify the hooks accordingly, and thank you for your suggestions. --TheLonelyPather (talk) 18:39, 4 June 2023 (UTC)

The lede ends vaguely:
"Charm quarks are found in various hadrons, and several bosons can decay into charm quarks."
Is it possible to give some examples? Or to characterize why the examples are obscure?
As I poked around I immediately ran into "charming" questions:

How is this thing/page related to Charm (quantum number)?
*How.. to Charmed baryon?
Other "charmed" things.
I'm sure that these question are trivial for those who know.  We don't ;-) Johnjbarton (talk) 21:04, 3 June 2023 (UTC)

Hi User:Johnjbarton,
These are really great questions!
Lede: I tend to refrain from throwing in things beyond the letters and numbers in the lede for readability, so I do not wish to put the sigmas and lambdas and xis. However, the J/psi meson should be there for sure.
Other articles: I feel like the relations between this page and "Charm (quantum number)" or "Charmed baryon" is best summarized in the lede of each of these articles. For example, "Charm (quantum number)" says:
Charm (symbol C) is a flavour quantum number representing the difference between the number of charm quarks (c) and charm antiquarks (cbar) that are present in a particle.
I also refrain from copying, or paraphrasing, the ledes of existing articles. Besides, I didn't manage to find a lot of scientific literature that explains the relationships between the charm quark and these concepts. It is true that in the realm of physics, the reader is supposed to have some knowledge beforehand. I will see what I can do.
Speaking of the devil... I just found a good introductory paper. I will crunch it out in my spare time. Feel free to edit the "charm quark" article as well.
Cheers, --TheLonelyPather (talk) 18:37, 4 June 2023 (UTC)
Lede: I like what you did!
Other articles: I agree about not summarizing the other ones. I was looking for a sentence that 1) linked the others 2) spoke to the relationship. Just something to give a flavor of the charm family of wiki articles. EG.
Charm quarks count towards the charm quantum number and contribute to charmed baryons.
Thanks Johnjbarton (talk) 19:57, 4 June 2023 (UTC)
On a tangent, do you think the article "Charm (quantum number)" could be deleted, and its content merged into this article? I think charm is rarely mentioned as a quantum number in the current physics literature. --TheLonelyPather (talk) 21:32, 5 June 2023 (UTC)
Merged and redirected could be a good option, but I don't think rarely mention recently in the current physics literature would be motivation. That would eliminate a large fraction of physics articles ;-). Rather I think reader experience should be a guide.  I don't prefer very short pages.
Here is some easy motivation: the quantum number comes with the quark, see:
"The c quark was postulated to carry a new quantum number charm, conserved by the strong interactions."

The only reference in page only lists the quantum number in one table. Johnjbarton (talk) 01:42, 6 June 2023 (UTC)
Thanks for finding the journal article! I will incorporate this into "Charm quark". Your finding makes a lot of things in life easier. -- TheLonelyPather (talk) 14:08, 6 June 2023 (UTC)
P. S. I have incorporated the idea of "charm as a quantum number" into the article. TheLonelyPather (talk) 14:22, 6 June 2023 (UTC)
I'd also like to point out that recent textbooks (Intro to Elementary Particles by Griffiths 2008) and (Modern Particle Physics by Thomson 2013) does not mention charm in the context of a quantum number :) TheLonelyPather (talk) 19:02, 4 June 2023 (UTC)

 TheLonelyPather (talk) 16:19, 24 July 2023 (UTC)

ADORABLE
great lines from this article 

In Glashow's words, the conjecture came from "aesthetic arguments".
However, these particles have zero total charm.

MASS - EXTREMELY NOT IMPORTANT COMMENT BUT
The charm quark is more massive than the strange quark
> 
The charm quark has more mass than the strange quark
The charm quark has a larger mass than the strange quark
??
I assume "massive" used here is the same mass from e=mc2 ?  Most normies won't be reading the charm quark article *BUT* I would caution that the colloquial meaning of "massive" (as used to describe "very big rock" or "huge spaceship" or "extremely significant shift in circumstances") might hang up people whose techie brain hemispheres stopped absorbing new info around algebra. It's just a little phrasing nuance that caught me up.

SINGULAR v PLURAL
Charm quarks can exist in either "open charm particles", which contains one or several charm quarks, 
Satellites can exist in either "solar systems," which contain one or several planets  
I don't know whether open charm particles are a single concept or a mystical physics something with multiple states but if it's kind of *one idea* I think this should be "which contain" instead of "which contains"
Kudos to all. I don't speak physics but clearly a very fine article. jengod (talk) 21:34, 7 August 2023 (UTC)

Hi @Jengod:
Thanks for your suggestions. I have edited the article according to your third point "SINGULAR v PLURAL". I think the "is more massive" expression is more succinct, but I think your point is valid.
You also moved the results of the scientific wagers (two of them!) to the end of the discovery section. I think that's also a valid move considering the sequence of the narrative.
Cheers, -- TheLonelyPather (talk) 21:01, 8 August 2023 (UTC)
Cheers back to you! I think the wagers move was already reverted but my argument for that is basic storytelling law: "Begin at the beginning, work through the middle, and when you get to the end, stop." Have the wager outcome told before the proven discoveries second feels like stepping on a punchline or telling the end in the middle. spoiler alert, etc etc. It's all good. Have a quarky day everyone. jengod (talk) 21:08, 8 August 2023 (UTC)