Talk:Lepton

message: The article states that "All known leptons have a negative or neutral charge."  That statement is meaningless, as there is no fundamental reason one is a particle and the other is an antiparticle; by convention for leptons the particle is the negative one
--anon
: The article no longer states this. Careful though: leptons can have positive, negative or neutral charge.
: RobPlatt 11:07, 25 Oct 2004 (UTC)
thread_title: Charge

message: Why is the Tau particle being called a Tauon throughout Wikipedia?
:It's not, any more. --DannyWilde 01:57, 29 November 2005 (UTC)
thread_title:  Tau/Tauon? 

message: This page lacks any info on lepton numbers.  I'm not sure I'm qualified to add it without making mistakes :) But here's a summary:
-There are three lepton numbers: electron, muon, and tau.  You can see a sumary here: http://hyperphysics.phy-astr.gsu.edu/hbase/particles/lepton.html#c7  That info should be probably be included in the articles table.
-Lepton numbers are conserved during decays.  Apparantly this is only approximately true and there are circumstance where the conservation breaks, but I don't know much about that. :)
:Good idea.  Added a sentence. -- ALoan (Talk) 10:39, 10 Feb 2005 (UTC)
thread_title:  Lepton numbers 

message: Perhaps the plural form of Lepton should be written as Lepta (from the Greek Λεπτά).
:This is never used in the particle physics communityJameskeates 12:32, 17 August 2006 (UTC)
thread_title:  Lepton/Lepta? 

message: On the origin of the term "lepton" (from the OED, citing L. Rosenfeld Nucl. Forces p. xvii):
:Following a suggestion of Prof. C. Møller, I adopt — as a pendant to "nucleon" — the denomination "lepton" (from λεπτόσ, small, thin, delicate) to denote a particle of small mass.
See also "Slender" in Greek.
The modern understanding of leptons in terms of their participation in the electroweak but not the strong force came significantly later. -- Xerxes 16:34, 28 November 2005 (UTC)
replies: text: That is a good reference. Don't you think that should go in the main body of the article? Lots of physics books give the etymology which I supplied, apparently incorrectly. --DannyWilde 01:57, 29 November 2005 (UTC)
replies: text: I've added the information. --DannyWilde 03:01, 29 November 2005 (UTC)
thread_title:  Etymology 

message: There is something I don't understand in this article: what keeps the electron and the electron neutrino together? and the same question for the muon and tau and their neutrinos. - Henry Likos 22.42 09 August 2006
:This is related to lepton number conservation mentioned above in the talk page. An electron and its neutrino have the same lepton number and this is conserved in all known interactions and the same for the muon and tau. A muon decaying to an electron for example must give off a muon neutrino so the muon number remains constant (as well as an electron anti-neutrino to balance the electron produced).Jameskeates 12:35, 17 August 2006 (UTC)
thread_title:  The Weak Doublet 

message: Feynman mentions observations of a larger lepton, c. 40,000 MeV he says, in a subscript to one of his books. Has this panned out?  —Preceding unsigned comment added by 66.44.102.150 (talk) 03:52, 10 September 2007 (UTC)
thread_title:  bigger lepton 

message: Just above the ethymology, I found this: "The names "mu" and "tau" seem to have been selected due to their places in the Greek alphabet; mu is seven letters after epsilon (electron), whereas tau is seven letters after mu." - should that not be in the ethymogoly section? Also, this seems like an inverified assumption by an unknown person and there's no reference or source. Does anybody know what the real story is?
SkyLined (talk) 20:42, 16 February 2008 (UTC)
thread_title:  Ethymology 

message: Why doesn't the table of propreties of leptons include their anomalous magnetic moment? If nobody objects, I'm going to include it. Dauto (talk) 05:52, 24 February 2009 (UTC)
replies: text: Sure go ahead. I suppose these anomalous ratios aren't known for quarks? Also could you review the mass of the neutrinos in the table. I'm not too sure about them.Headbomb {ταλκκοντριβς – WP Physics} 10:52, 24 February 2009 (UTC)
thread_title:  Anomalous Magnetic Moment 

message: The lepton isodoublets figure had the leptons with the wrong isospin assignments -- every convention I've ever seen has the electric charge of the upper member of the isodoublet one unit larger than that of the lower member (in accordance with Q = T3 + Y).  Apologies to Headbomb for replacing your figure. HEL (talk) 03:43, 1 April 2010 (UTC)
thread_title:  Fixed lepton isodoublets figure 

message: - The diagrams in 'Electromagnetic interaction' and 'Weak interaction' , 
showing two electrons distructing to create a photon (on the 1'st) and a Z0 (on the 2'nd) - 
are incorrect. 
In both cases - these should be an Electron (e-) and a Positron (e+) - not as was drawn. 
(94.159.221.248 (talk) 10:28, 11 October 2010 (UTC)
replies: text: No. Look at the arrows.  Electron in, electron out. --Michael C. Price talk 10:30, 11 October 2010 (UTC)
replies: text: Well, actually the arrows on the lepton lines don't say much in this respect as they just indicate the flow of lepton number. Even so, the diagrams are correct if you read then as going from left-to-right. (Also, note that they are interaction vertices not full diagrams, as such it contains no assumptions about particles being on-shell.TimothyRias (talk) 10:36, 11 October 2010 (UTC)
replies: text: The arrows do not all represent lepton number flow.  But they are all correct, anyway. --Michael C. Price talk 10:46, 11 October 2010 (UTC)
thread_title:  Incorrect diagrams 

message: Introduction says "Thus electrons are stable and the most common of leptons in the universe..."
Isn't this incorrect and neutrinos being the most common lepton by far?
IlkkaP (talk) 17:04, 5 December 2010 (UTC)
replies: text: I think so, by several orders of magnitude, if there exists a cosmic neutrino background. The sentence obviously refers to electrons being the most common charged lepton. I've changed it to say so explicitly.TimothyRias (talk) 18:17, 5 December 2010 (UTC)
replies: text: Unless the cosmic neutrino background contains an approximately equal number of antineutrinos.  Does it? I tried looking it up at Timeline of the Big Bang, but couldn't see any mention of the neutrino dissociation event. --cheers, Michael C. Price talk 12:42, 6 December 2010 (UTC)
replies: text: See  page 81 and forward, for a discussion of neutrino decoupling and the neutrino number density.TimothyRias (talk) 12:56, 6 December 2010 (UTC)
thread_title:  Most common lepton? 

message: The first sentence in the article is completely imprecise and wrong, since it is bothmisleading and fails to distinguish leptons from other elementary particles like quarks:
“A lepton is an elementary particle and a fundamental constituent of matter.”
Leptons do include neutrinos, which are not ordinary “matter”, but leptons don't include quarks that undergo strong interactions and are present in the nucleons of every atom!  I suggest that the first sentence should be replaced with:
“A lepton is a elementary particle which does not undergo strong interactions, but is subject to the Pauli exclusion principle (apart from quarks and bosons, all known particles in the universe are leptons).”
NC
Photocopier (talk) 15:47, 9 November 2012 (UTC)
thread_title: First sentence is wrong: it fails to deliver any real concise information

message: observation ,discovery,  when a secondary plasma field is generated through the interaction of particular metals, ie stainless steel mesh., and the primary plasma field, the interaction with that secondary field and steel wool ie.steel wool wrapped around secondary glass .,,then bringing a piece of stainless steel to it, causes the secondary field to increase and lite the wool on fire .  a simple plasma ball with various gasses, and a mercury vapour high frequency bulb for secondary interaction. interesting to say the least. Ronald sykes.50.93.20.150 (talk) 05:37, 13 July 2013 (UTC)
thread_title:  secondary plasma field 

message: Can someone please find a place to add these formulas for lepton mass ratios. 
Leptons        	Formula                                                                                                                                  	Experimental value
Muon / electron	\frac{m_\mu}{m_e}=\left ( \frac{\alpha^{-2}}{2\pi} \right ) ^\frac{2}{3}\frac{(1+2\pi\frac{\alpha^2}{2})}{(1+\frac{\alpha}{2})}=206.76828	(206.72827)
Tau / muon     	\frac{m_\tau}{m_\mu}=\left ( \frac{\alpha^{-1}}{2} \right ) ^\frac{2}{3}\frac{(1+\frac{\alpha}{2})}{(1-4\pi\alpha^2)}=16.817             	(16.817)
Tau / electron 	\frac{m_\tau}{m_e}=\left ( \frac{\alpha^{-3}}{4\pi} \right ) ^\frac{2}{3}\frac{(1+2\pi\frac{\alpha^2}{2})}{(1-4\pi\alpha^2)}=3477.2      	(3477.3)
KnowMoreThanU (talk) 15:31, 14 December 2014 (UTC)
replies: text: What is the source? Something like this looks like numerology – and there are many examples in physics of formulae like this being presented that match experimental figures extraordinarily well, but that have no basis beyond that. This encyclopaedia article is not the place for such examples. —Quondum 18:24, 14 December 2014 (UTC)
replies: text: Inconvenient for the Standard Model that these exist I grant you but, no, not numerology. KnowMoreThanU (talk) 21:59, 14 December 2014 (UTC)
replies: text: With an answer like that, you can't expect anyone to take notice. —Quondum 22:11, 14 December 2014 (UTC)
replies: text: I deleted this section. It is purely the speculative work of one person. Regardless of its possible veracity, (which has not been shown), it does not belong here, as it is not generally accepted in the physics community. LordKitchenersValet (talk) 23:15, 26 July 2022 (UTC)
thread_title:  Mass ratios 

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thread_title:  External links modified 

message: The observed violation of lepton universality (last paragraph of section Universality) has, as of yet, not reached the level of significance usually required to claim a discovery (5 sigma deviation from expectation based on previously accepted model), so there is no reason to get all worked-up. Yet, if these observations keep holding up in further experiments, the implications are tremendous. The paper by Ciezarek et al., referenced in our article, ends with, "A confirmation of new-physics contributions in these decays would shake the foundations of our understanding of matter and trigger an intense programme of experimental and theoretical research." "New physics" refers to physics beyond the Standard Model, involving new particles and interactions. Is it worth pointing this out in the article?  --Lambiam 19:34, 20 July 2017 (UTC)
replies: text: I wiki-linked to new physics. I don't think it's worth spelling it out here: people can just click through to the main article. If any detail is to be added, it should be more about what the anomalies are (i.e. P5´, R(K), R(K*), R(D), R(D*)) or at least cite the experimental papers. It might be worth mentioning some of the more common proposals for new physics, such as Z´s and leptoquarks. — dukwon (talk) (contribs) 20:26, 20 July 2017 (UTC)
thread_title:  Implications of violation of lepton universality 

message: Why are the anti-leptons mentioned in the introduction and not the anti-quarks?  — Preceding unsigned comment added by Koitus~nlwiki (talk • contribs) 23:03, 3 March 2020 (UTC)
thread_title:  And what about the anti-quarks? 

message: What could this be? 2A00:20:C001:E5D9:588A:CCCF:E982:75E (talk) 10:41, 19 November 2021 (UTC)
thread_title:  Tgf verified L vioaltion PASSED 

message: The section Etymology ascribes the coinage to Rosenfeld, said to have "first used" it in 1948. However, Abraham Pais wrote in his book A Tale of Two Continents, referring to a paper he supposedly co-wrote with Christian Møller presented at the International Conference on Fundamental Particles and Low Temperatures held at the Cavendish Laboratory, Cambridge, UK, on 22–27 July 1946,
:
The Conference Proceedings appeared in print in two volumes in 1947, published by Taylor & Francis under the title Report of an International Conference on Fundamental Particles and Low Temperatures. The article in question appeared in Volume 1, starting on page 184, and the quoted addition appears indeed as a footnote on page 184. Confusingly, however, the paper in question, titled "The possible existence of mass spectra of fundamental particles" and occupying a single page, page 184, lists only C. Møller as author. In any case, this appeared earlier than Rosenfeld's book.  --Lambiam 20:51, 21 January 2023 (UTC)
thread_title:  Who coined the term ''lepton''? 

message: In the first paragraph it it says "Two main classes of leptons exist: leptons (also known as the electron-like leptons or muons), and neutral leptons". Then it says "The best known of all leptons is the electron."
This makes me (an uninformed reader) wonder if "electron-like leptons" are the same thing as "electrons" or if the electron is not in one of the two main classes of leptons. Yellowpelican (talk) 16:22, 21 September 2023 (UTC)
thread_title:  "Electron-like lepton" vs "electron"