Talk:J/psi meson

A fact from J/psi meson appeared on Wikipedia's Main Page in the Did you know column on 29 September 2004. The text of the entry was as follows:

Did you know... that the discovery of the J/Ψ particle in 1974 earned two physicists the Nobel prize as it confirmed the idea that baryonic matter (such as the nuclei of atoms) is made out of quarks?

A record of the entry may be seen at Wikipedia:Recent additions/2004/September.

Wikipedia

Untitled[edit]

Is there any alternative spelling without the slash / solidus in the title? It makes the article's location look odd in browser... Ian Cairns 06:11, 29 Sep 2004 (UTC)

No, I don't think so. I actually first tried to use J/Ψ particle as title, but ddn't figure out how to make the Wiki correctly interprete the Ψ instead of displaying the HTML entity. Simon A. 08:23, 29 Sep 2004 (UTC)

The name of the particle is J/ψ, with a small psi. I expanded on the prehistory.--192.35.35.36 23:01, 1 Feb 2005 (UTC)

The name ψ was chosen before they had any spark chamber photographs. The correct story of the name can be found in Crease and Mann The Second Creation.--192.35.35.35 16:45, 3 Feb 2005 (UTC)

A different "J/psi" can be found on the label of some Valdespino sherry: [1] Look down for more instances of the symbol.--192.35.35.35 18:14, 8 Feb 2005 (UTC)

the term "charmonium"[edit]

I found the therm "charmonium" used as a more general term, not just meaning J/ψ but also ψ and (maybe?) other charm-anticharm mesons (such as η_c or χ_c). Is that correct? Specifically they used the expression "charmonium spectrum" to reffer to all those different things. If that would be true, maybe the "charmonium" page should be a dissambiguation page or a list of links instead of a plain redirect. --Xavier 01:30, 2005 Apr 3 (UTC)

You are right. (Yes, the term refers to the other ψ's as well. For the non-ψ particles I'm not sure either.) Maybe fix it if you find the time. Simon A. 12:35, 4 Apr 2005 (UTC)

Charmonium is any bound charm-anticharm system. This can be Psi (incl J/Psi), η_c, chi;_c and h_c

For nomenclature see http://pdg.lbl.gov/2006/reviews/namingrpp.pdf Christoph Scholz 16:04, 9 August 2006 (UTC)[reply]

I fixed this by moving it after the paragraph on excited states. TimAdye (talk) 02:28, 25 March 2008 (UTC)[reply]

Infobox[edit]

I have updated the infobox, I belive it is not fully filled in though. -Ravedave ^{(help name my baby)} 01:28, 5 October 2006 (UTC)[reply]

The "gypsy"!?[edit]

I have never heard this informal name. Can anyone supply a reference? (I tagged it with "citation needed".) HEL 00:34, 2 February 2007 (UTC)[reply]

J/psi lifetime[edit]

The introduction of the article states: This lifetime was about a thousand times longer than expected. Why is this important? On what physics was the expectation based, and what interesting property of the J/psi gave rise to the longer lifetime? I tagged this with "citation needed" too. (Sorry for being a pest, but it sounds odd otherwise.) HEL 00:42, 2 February 2007 (UTC)[reply]

Good point. Not sure, but I think this refers to the GIM mechanism, referred to further down in the article. Charm was needed to make the theoretical estimates of strange particle lifetimes get longer. I'm guessing they didn't get all the mixing angles right at first.

Hey so, sorry to reply to this comment 12 years later, well I guess even 1 year ago I wouldn't have known this, but the lifetime being super long is actually very relavent. So first the Heisenburg uncertainty principle relates time and energy uncertainty, basically saying, the more time certainty you have (the less Delta t) the more energy uncertainty you must have (more delta E). So because the lifetime is so long Delta t is big, thus delta E is very small, so small in fact that it took Richter's team 3 months to find it. according to this article from ArXiV, its lifetime was 1000 times longer than particles of comparable mass, and this stability in part sparked the november revolution, with 700 papers being written about the discovery in the following year. Aurora_{(User:Horkak)} (talk) 04:10, 4 December 2019 (UTC)[reply]

The Name[edit]

I edited the paragraph on the naming of excited states to correct a few inaccuracies. ψ is only used to refer to vector states (orbitally excited states of the J/ψ; η_c and χ_c are also charm-anticharm bound states, but with different spin-parity). The ψ(3686) is more commonly known as the ψ(2S). I added a reference to the official PDG naming scheme. TimAdye (talk) 02:43, 25 March 2008 (UTC)[reply]

Watershed[edit]

...did the J/psi reveal its existence. This discovery was a watershed in establishing the Standard Model, because the J/psi proved to contain a new type of elementary constituent of matter - the charmed quark .Ref —Preceding unsigned comment added by Lucian Sunday (talk • contribs) 21:24, 25 July 2008 (UTC)[reply]

Translation into Chinese Wikipedia[edit]

The 21:44, 29 November 2009 LaaknorBot version of this article is translated into Chinese Wikipedia.--Wing (talk) 20:12, 2 December 2009 (UTC)[reply]

Hadron overhaul[edit]

Please give input at Talk:Hadron#Hadron overhaul. Thanks. Headbomb {^ταλκ_{κοντριβς} – WP Physics} 01:59, 24 January 2010 (UTC)[reply]

Citation Needed in intro[edit]

Why is a citation needed for the statement that the lifetime is 3 orders of magnitude longer than expected? It's obviously "expected" to be a strong decay, on the order of 10^-24 s lifetime. Seems like a generally accepted rule here, you could basically cite any intro particle book. 209.150.56.118 (talk) 20:10, 27 July 2010 (UTC)[reply]

Pronunciation[edit]

The article could perhaps use a small note about pronunciation. Anyone who doesn't know what a psi is would be completely baffled about the whole thing mostly due to an unpronounceable character. 8ty3hree (talk) 04:32, 8 November 2012 (UTC)[reply]

Psion[edit]

I am adding the term psion and a ref back to the lede, following discussions at talk:psion#Requested move 22 September 2014.

Many more refs readily available, see that discussion and Google books. Andrewa (talk) 21:54, 25 September 2014 (UTC)[reply]

Done. Andrewa (talk) 21:57, 25 September 2014 (UTC)[reply]

POV comments[edit]

In the section titled "Background to Discovery," there is somewhat loaded language regarding the preexistence of the GIM mechanism. It can be corroborated that the GIM mechanism existed, and that it correctly predicted the existence of a fourth quark. But saying things like "These predictions were ignored. The work of Richter and Ting was done for other reasons" makes it sound like someone had an ax to grind. Specifically, someone who made edits on 1 February 2005.

So, while I am tempted to take out that entire bit, I'll settle for the time being adding citation requests. Merryjman (talk) 20:36, 13 April 2016 (UTC)[reply]

Hey, not to reply to your comment 3 years later, but I was reading [[2]] article for a class, which states that the explicit goals of either experiment was not to search for the charmonium, but I agree that the language that they ignored it is loaded and probably incorect. I'm writing a paper on it right now, haha, and I say in the paper that they were certainly aware of all of this given the chaos going on in the scientific community they had a phd in. Aurora_{(User:Horkak)} (talk) 03:18, 4 December 2019 (UTC)[reply]

Assessment comment[edit]

The comment(s) below were originally left at Talk:J/psi meson/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

Although I'm a physics major (B.Sc. McGill 1966), and have been an avid amateur follower of science topics since then, I don't feel qualified to comment on the contents of this page in terms of theory, but I do take issue with the chronology. In 1966 I thought I was starting to understand the "zoo" of particles in terms of charts resembling the Mendeleev table of elements, but the young physics students were thrown a curve with talk of a hypothetical "J-particle", which was portrayed at the time like a Holy Grail particle (not unlike how the Higgs Boson is portrayed today), and I folded like a cheap tent, knowing that the glimmering of understanding I had worked so hard to acquire was being blown out of the water by the J-particle, in a way beyond repair. Yes, that was the particle that scared me out of physics in 1966, and so I am surprised to see an article which dates it somewhere in the mid-1970s. Maybe somebody could check that out.

Substituted at 23:20, 26 June 2016 (UTC)

Figure[edit]

I think the new dimuon mass spectrum from CMS (in which other peaks are seen besides the J/psi) plus a more detailed caption) is an improvement over the Fermilab isolated J/psi mass peak as it gives more context Paco Barradas (talk) 02:00, 27 February 2020 (UTC)Paco Barradas[reply]