Talk:Charm quark

Accessibility

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)

Charity

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)

Origin and naming

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)

Conflict with charm quark

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

Fourth or third?

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 {^ταλκ_{κοντριβς} – WP Physics} 14:34, 18 October 2009 (UTC)

New Reference

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 q_s and q_c 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)

Point of Contention within the data

Given that from the data m_c is 1.27+0.07
−0.11 GeV/c² and m_b is 4.20+0.17
−0.07 GeV/c² by (MS scheme) and 4.68+0.17
−0.07 GeV/c² (1S scheme) then m_b-m_c as currently stated by PDG source of 3.43+0.05
−0.05 GeV/c² is above the mathematically evaluated m_b-m_c where (MS scheme) is used for m_b (3.00+0.21
−0.21 GeV/c²), and is completely interior to m_b-m_c where (1S scheme) is used for m_b (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)