Talk:Bottom quark

Mass

Since no quark can exist in a free state (ie, unbounded to another quark), how can we claim a single value for the bottom quark's mass? Its effective mass is going to be different depending on which meson it's in, just like the effective mass of protons in a nucleus are not equal to the mass of a free proton. We should make a note of this where we give the mass, no? Miraculouschaos 16:26, 1 August 2007 (UTC)[reply]

Bottom vs Beauty

The article writes:

On its discovery, there were efforts to name the bottom quark "beauty", but "bottom" became the predominant usage.

Is this really true? People indeed refer slightly more often to "bottom quark" than "beauty quark", but the _b_ quantum number is more often referred to as units of beauty. A simple search of beauty and bottom in article titles in spires returns 653 and 1146 hits respectively. Pkoppenb (talk) 06:40, 12 October 2009 (UTC)[reply]

As far as I know, it's the dominant usage in modern textbooks on the topic (local usage can obviously be different and probably depends on the laboratory more than on the country). As for the b quantum number, see Bottomness. Headbomb {^ταλκ_{κοντριβς} – WP Physics} 06:57, 12 October 2009 (UTC)[reply]

Some canonical citations are needed for the original naming, the strands of usage of different names, and the current situation. The SPIRES data is interesting. For example, here is a contemporay reference from CERN using beauty:

https://cerncourier.com/a/beauty-baryons-strike-again/

Mikhailfranco (talk) 15:07, 8 January 2020 (UTC)[reply]

LHCb and CMS prefer beauty, ATLAS, Belle II, Belle, BaBar, CDF and maybe D0 prefer bottom. PDG calls it bottom. I didn't find a paper from ALICE using one of these words. Bottom is clearly the more common word. --mfb (talk) 05:27, 9 January 2020 (UTC)[reply]

Harari's quark model

See Talk:Quark#Harari's quark model. Headbomb {^ταλκ_{κοντριβς} – WP Physics} 00:05, 22 February 2010 (UTC)[reply]

H. Harari actually COINED the names of the "top" and "bottom" quarks. Harari was the first to propose a model of six quarks and six leptons, naming the two new quarks “top” and “bottom” (names presently accepted by all), and predicting the existence of six leptons. In August 1975, at the Stanford International Particle Physics conference he presented, for the first time ever, the full synthesis accepted today as “the standard model” of six quarks and six leptons. Its seems that the authors of this page arent from the field of HEP Barak90 (talk) 10:28, 22 February 2010 (UTC)[reply]

Physical mass instead of mass in different renormalization schemes

Hi everyone, I was just wondering if it wouldn't be a bit more reasonable to quote the physical mass instead of the masses in different renormalization schemes, as this seems a bit too technical to me and certainly isn't what the layman would refer to as mass. Any opinions on that? Jaschau (talk) 12:09, 3 June 2010 (UTC)[reply]

What do you mean by "physical mass"? TimothyRias (talk) 13:31, 3 June 2010 (UTC)[reply]

My original thought was basically the mass that occurs as a pole in the propagator. Or a bit more quantum mechanically spoken, if we consider the Hilbert space of our system and choose our base states such that they are eigenstates both to the Hamiltonian H and the operators

P^{\mu }

and

W^{3}={\frac {1}{2}}\epsilon _{\mu \nu \rho \sigma }J^{\nu \rho }P^{\sigma }

that represent the action of the Poincaré group on our states, the eigenvalue of the operator

P^{2}=P_{\mu }P^{\mu }

. If I'm not mistaken, the pole mass is also given in the paper of the PDG quoted in the article. Nevertheless, I've just read http://pdg.lbl.gov/2009/reviews/rpp2009-rev-quark-masses.pdf (especially p. 13) and it seems that things are a bit more complicated due to the fact that pure quarks aren't observed in nature because of confinement. Obviously, the full quark propagator doesn't have a pole, such that the pole mass doesn't make any sense outside of perturbation theory. But still the pole mass is the mass one would use in perturbation theory, which makes me think that it might still be worth quoting it. Jaschau (talk) 16:36, 6 June 2010 (UTC)[reply]

As you pointed out yourself, the pole mass is not meaningfull for the case of the b quark because of confinement. That's just the way it is. In other words, the pole mass is the mass of the free particles but free quarks do not exist except at high enough enegies due to asymptotic freedom. But those high energy masses are significantly affected by renormalization and that's why the masses in different renormalization schemes are quoted. The layman is obviouly not aware of all that but this complications come with the territory. There is no way around it. Dauto (talk) 23:16, 6 June 2010 (UTC)[reply]

New Reference

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) 20:32, 2 August 2010 (UTC)[reply]

No, objections here. We should strive to keep the value up to date with the PDG. TimothyRias (talk) 10:23, 3 August 2010 (UTC)[reply]

Woot! Shiny new numbers! Headbomb {talk / contribs / physics / books} 06:02, 4 August 2010 (UTC)[reply]

Chi_b(3P) particle

I believe this section belongs in Quarkonium article, as this new particle is one of the bottomonium states, which are already mentioned earlier in this article, but not in detail. Either more information about the bottomonium in general should be provided here, or this particle should not be listed at all. — Preceding unsigned comment added by 213.17.130.201 (talk) 23:07, 22 December 2011 (UTC)[reply]

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