Why is there still disagreement over the b quark's name?

Click For Summary

Discussion Overview

The discussion centers around the terminology used for the b quark, specifically the use of "beauty" versus "bottom." Participants explore the historical context, current usage in literature, and potential reasons for the ongoing dual terminology in particle physics.

Discussion Character

  • Debate/contested
  • Historical
  • Meta-discussion

Main Points Raised

  • Some participants note that "beauty" and "bottom" are used interchangeably in different physics papers, with no clear consensus on which term is preferred.
  • One participant references the International Union of Pure and Applied Physics, stating that the names for quarks are considered mnemonics and that "top" and "bottom" have become conventional.
  • Another participant suggests that "top" and "bottom" are easier to pronounce than "truth" and "beauty," which may contribute to their popularity.
  • Some express a preference for "beauty" when describing hadrons, suggesting it sounds nicer, while others observe that "bottom" is more commonly used.
  • Humorous remarks are made about the dual terminology, with some participants noting the charm of the name "beauty" in the context of particle physics.
  • There are discussions about the rarity of certain decay processes and the challenges in measuring them, which may indirectly relate to the terminology debate.

Areas of Agreement / Disagreement

Participants do not reach a consensus on why the dual terminology persists, with multiple competing views remaining on the preference for "beauty" versus "bottom." The discussion reflects a variety of opinions and experiences without a definitive resolution.

Contextual Notes

Some participants mention historical usage and personal experiences from decades ago, indicating that terminology may vary based on context and individual preference. The discussion also touches on the influence of geographical and institutional factors on terminology.

ohwilleke
Gold Member
Messages
2,667
Reaction score
1,633
Some physics papers today describe the b quark as a beauty quark. For example:

"Displaced B−c mesons as an inclusive signature of weakly decaying double beauty hadrons", T. Gershon, A. Poluektov (Submitted on 15 Oct 2018)

Others physics papers today refer to b quarks as bottom quarks. For example:

"Higgs production in association with bottom quark pair at LHC"
Wen-Tao Huang, Hong-Lei Li, Shi-Yuan Li, Peng-Cheng Lu, Zong-Guo Si, Ying Wang, Zhong-Juan Yang (Submitted on 28 Sep 2018)

The b quark is a particle that was theoretically predicted to exist in 1973 and first observed experimentally in 1977.

But, here we are in late 2018 and there still doesn't seem to be a consensus (if there is actually a widely adopted rule regarding the contexts in which you use one versus the other, that would also be an acceptable answer to this question).

Is there are pattern regarding who uses which terminology in terms of geography, educational pedigree, or position on issues in physics, or is it just a matter of personal preference? Are there style guides addressing the issue at places like CERN and Fermilab and Jefferson Labs?

Why does the dual terminology persist?
 
Last edited:
Physics news on Phys.org
From the International Union of Pure and Applied Physics:

http://iupap.org/wp-content/uploads/2014/05/A4.pdf (page 12)

The names for quarks are the symbols themselves; the names ‘up’, ‘down’,
‘charm’, ‘strange’, ‘top (truth)’ and ‘bottom (beauty)’ are to be considered only as mnemonics for these symbols.
(where "the symbols" are u, d, c, s, t, b.)

I remember some people using 'truth' and 'beauty' when I was a grad student in particle physics 35-40 years ago, but 'top' and 'bottom' became conventional. I'm rather surprised to see someone use 'beauty' nowadays, although I admit I haven't paid attention to this particular issue. The paper you cited is a preprint that has not yet gone through editorial review by a journal. I don't know whether a journal editor would change it to 'bottom' or just 'b' for publication. It might depend on the journal.
 
  • Like
Likes   Reactions: ohwilleke
top / bottom is far easier to speak than truth / beauty. Since particle physics is very international, this might have been the reason.
 
I haven't seen the term "truth" used for a t quark for ages (maybe never). But, see "beauty" used for a b quark on a regular basis, including in published articles (I link to pre-prints simply because its easier to quickly find examples and I review them every day). I wonder if beauty just sounds nicer when describing hadrons with it as a component than bottom.
 
ohwilleke said:
I wonder if beauty just sounds nicer when describing hadrons with it as a component than bottom.
I think that is the point. I see "bottom" more often, but some people like "beauty", and everyone understands them, so there is no strong incentive to unify it.
 
  • Like
Likes   Reactions: dlgoff
the beauty is in the bottom... :-D
 
  • Like
Likes   Reactions: eloheim
There is certainly some charm to the name beauty. Especially as the two often come together in particle physics. You have b->c as dominant decay and often charm as background as well. Or B hadrons as background if you study charm.
 
  • Like
Likes   Reactions: eloheim and ohwilleke
mfb said:
There is certainly some charm to the name beauty. Especially as the two often come together in particle physics. You have b->c as dominant decay and often charm as background as well. Or B hadrons as background if you study charm.
Does this imply truth is often strange?
 
  • Like
Likes   Reactions: Klystron
MathematicalPhysicist said:
the beauty is in the bottom... :-D
Especially at CLEO. :cool:
 
  • #10
jtbell said:
Especially at CLEO. :cool:
I don't think I've ever seen that many references (198) on a Wikipedia article.
 
  • #11
Wikipedia has a list of articles with most references
The CLEO article is exceptionally detailed due to this edit.
fresh_42 said:
Does this imply truth is often strange?
t->Wb is the only decay observed so far. For the other quarks the status is better, with all the transitions seen. t->Ws should be the second-most decay, but so rare and so hard to distinguish from background that it won't be measured anytime soon (unless it is much more frequent than predicted).
 
  • #13
mfb said:
t->Ws should be the second-most decay, but so rare and so hard to distinguish from background that it won't be measured anytime soon (unless it is much more frequent than predicted).

Or, unless we find some clever way to distinguish it from background statistically, for example, by carefully integrating data about angular momentum and linear momentum of decay products in each decay chain to distinguish t->Ws from decays such as c->Ws, so that lots of background can be efficiently distinguished.

One could also measure the rare, but far less background ridden process s->Wt for highly energetic s quarks, and get the inverse from which the measured rate could be determined.
 
  • #14
mfb said:
t->Ws should be the second-most decay

Actually, I believe it's $$t \rightarrow W + b + \gamma$$.
 
  • #15
ohwilleke said:
Or, unless we find some clever way to distinguish it from background statistically, for example, by carefully integrating data about angular momentum and linear momentum of decay products in each decay chain to distinguish t->Ws from decays such as c->Ws, so that lots of background can be efficiently distinguished.

One could also measure the rare, but far less background ridden process s->Wt for highly energetic s quarks, and get the inverse from which the measured rate could be determined.
Good luck...
Vanadium 50 said:
Actually, I believe it's $$t \rightarrow W + b + \gamma$$.
Didn't think about that. It doesn't sound easy to measure either.