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I'm not a physicist, but the page states It should be understood however that it is not possible to create only electrons (or only protons) without violating the conservation of the electric charge. In other words, the conservation of the electric charge requires an equal number of electrons and protons. However, I'm not aware of any such requirement. Do they mean electrons and positrons? 65.191.115.91 ( talk) 22:24, 17 April 2008 (UTC)
I am a physicist, and I noticed the same issue. Unfortunately, I'm not convinced that simply replacing "proton" with "positron" everywhere it occurs is the most accurate solution. Ultimately, the conservation of electric charge merely requires that the total charge of all positively-charged particles equal the total of all negatively-charged ones. There are at least three ways to produce electrons. First, which the original author may have been considering, is the beta decay of a neutron, resulting in an electron, an electron antineutrino, and a proton. Second, production of electron-positron pairs can occur. Third, a muon will decay into an electron, a muon neutrino, and an electron antineutrino. In only the first example are protons and electrons produced at the same rate. Any thoughts on how to best represent the author's intended meaning? Tstroman ( talk) 18:36, 25 February 2009 (UTC)
Hi Headbomb,
I saw your changes to "leptogenesis" and I tend to disagree. The example reaction I gave
gamma gamma ---> nu nu
shows that you can create standalone leptons, namely the two neutrinos in final state, without violaing the electric charge. It is true this cannot be done in the standard model, but this is just an irrelevant remark. Indeed, in order to implement leptogenesis, you need to modify the standard model anyway. So why to write irrelevant statements?
I'd rather recommend as flowchart of this entry of Wiki: 1. Definition of Lepto. (1st paragraph as it stands) 2. Lepto. does not work in the standard model (3rd paragraph, as it stands, beginning with "Baryogenesis") 3. Then the subsequent paragraph (4th paragraph as it stands). 4. Eventually, the paragraph beginning with "The next step after leptogenesis..." contained in the 2nd paragraph, which in my view is excessive and a bit misleading from the main topic, but not wrong.
Best, Francesco
PS I forgot to mention that in the standard model, minimally modified to consider the existence of massive neutrinos and flavor oscillations, the reaction I mentioned occurs necessarily.
Hi Headbomb,
thanks for the reply and I do agree that beta decay is irrelevant but i am sorry this does not go to the point I tried to make.
Incidentally, I do not understand why I write quite clearly and unambiguosly
gamma gamma --> nu nu
and you transform what I write into something different
gamma gamma --> nu bar-nu
which is evidently irrelevant just as the beta decay.
I make another try to explain this point, assuming you know some quantum field theory. Consider the Feynman diagram:
. gamma entering . . . ----------------- outcoming neutrino | ! virtual Majorana neutrino | ----------------- outcoming neutrino . . . . gamma entering .
The coupling with gamma is very small but it is stipulated by virtual W. If you like it better, replace the gamma with a Z boson and consider Z Z ---> nu nu. The intermediate virtual neutrino is assumed to be massive, as suggested by experiments. Furthermore, assume it to be Majorana particle, which is compatible with all we know. You see that we create two neutrinos.
Let me make another example, possibly more standard. Consider again massive Majorana neutrino. Everybody knows (and if he/she doesn't can learn on that in Wiki) that by the neutrinoless double beta decay, a couple of electrons are formed.
My bottomline is
1) The renormalizable version of the standard model predicts that lepton number is conserved or if you want you do not produce net lepton number at any perturbative level. This is what you want to stress but as it is written it is not correct, see next point. What it is missing is a precise definition of what you are discussing "renormalizable standard model at perturbative level".
2) As it is written later in "Leptogenesis" this is not true at non perturbative level, since sphaleron can create lepton number. However this is not sufficient quantitatively to create enough leptons and realize the idea of Sakharov (it is not a principle problem). This is written already clearly and contradicts the part we are discussing: indeed it is stated "This means that the Standard Model is in principle able to provide a mechanism to create baryons and leptons"
3) But even worse, the renormalizable version of standard model is also inadequate to explain the fact that neutrinos are massive. If we include the first non-renormalizable operator, lepton number is violated immediately.
This is why I insist in recommending to remove the wrong (or misleading or irrelevant depending on what we discussing) statement that you recommend to maintain.
Best, Francesco
Hi Headbomb
please read "Sphaleron" on Wiki, it is considered part of the standard model.
Then it is evident to me that you "do feel that the article is not misleading on that point" otherwise we would not discuss. This is why you use the word contradiction is quotation marks while I use it without. However, if we can reach an agreement on the meaning of the word using the vocabulary, and then we read the text as it stands:
1) "in the currently accepted model for the elementary interactions, the so called Standard Model, it is not possible to create only "standalone" leptons"
2) "the Standard Model is in principle able to provide a mechanism to create baryons and leptons"
I believe we could agree.
I think the "physics" indication in the title is abundant. Are there any definitions of leptogenesis in other field? Correct me if I'm wrong.
Hhthoj ( talk) 04:22, 20 August 2019 (UTC)
The result of the move request was: page moved. ( non-admin closure) ~SS49~ {talk} 14:47, 9 June 2020 (UTC)
Leptogenesis (physics) → Leptogenesis – No reason for a dab page with two entries, one of which is only an alternative name. Create hatnote to Book of Jubilees per WP:TWODABS. ― Justin (koavf)❤ T☮ C☺ M☯ 01:15, 24 May 2020 (UTC) —Relisting. b uidh e 04:32, 2 June 2020 (UTC)
![]() | This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||||
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I'm not a physicist, but the page states It should be understood however that it is not possible to create only electrons (or only protons) without violating the conservation of the electric charge. In other words, the conservation of the electric charge requires an equal number of electrons and protons. However, I'm not aware of any such requirement. Do they mean electrons and positrons? 65.191.115.91 ( talk) 22:24, 17 April 2008 (UTC)
I am a physicist, and I noticed the same issue. Unfortunately, I'm not convinced that simply replacing "proton" with "positron" everywhere it occurs is the most accurate solution. Ultimately, the conservation of electric charge merely requires that the total charge of all positively-charged particles equal the total of all negatively-charged ones. There are at least three ways to produce electrons. First, which the original author may have been considering, is the beta decay of a neutron, resulting in an electron, an electron antineutrino, and a proton. Second, production of electron-positron pairs can occur. Third, a muon will decay into an electron, a muon neutrino, and an electron antineutrino. In only the first example are protons and electrons produced at the same rate. Any thoughts on how to best represent the author's intended meaning? Tstroman ( talk) 18:36, 25 February 2009 (UTC)
Hi Headbomb,
I saw your changes to "leptogenesis" and I tend to disagree. The example reaction I gave
gamma gamma ---> nu nu
shows that you can create standalone leptons, namely the two neutrinos in final state, without violaing the electric charge. It is true this cannot be done in the standard model, but this is just an irrelevant remark. Indeed, in order to implement leptogenesis, you need to modify the standard model anyway. So why to write irrelevant statements?
I'd rather recommend as flowchart of this entry of Wiki: 1. Definition of Lepto. (1st paragraph as it stands) 2. Lepto. does not work in the standard model (3rd paragraph, as it stands, beginning with "Baryogenesis") 3. Then the subsequent paragraph (4th paragraph as it stands). 4. Eventually, the paragraph beginning with "The next step after leptogenesis..." contained in the 2nd paragraph, which in my view is excessive and a bit misleading from the main topic, but not wrong.
Best, Francesco
PS I forgot to mention that in the standard model, minimally modified to consider the existence of massive neutrinos and flavor oscillations, the reaction I mentioned occurs necessarily.
Hi Headbomb,
thanks for the reply and I do agree that beta decay is irrelevant but i am sorry this does not go to the point I tried to make.
Incidentally, I do not understand why I write quite clearly and unambiguosly
gamma gamma --> nu nu
and you transform what I write into something different
gamma gamma --> nu bar-nu
which is evidently irrelevant just as the beta decay.
I make another try to explain this point, assuming you know some quantum field theory. Consider the Feynman diagram:
. gamma entering . . . ----------------- outcoming neutrino | ! virtual Majorana neutrino | ----------------- outcoming neutrino . . . . gamma entering .
The coupling with gamma is very small but it is stipulated by virtual W. If you like it better, replace the gamma with a Z boson and consider Z Z ---> nu nu. The intermediate virtual neutrino is assumed to be massive, as suggested by experiments. Furthermore, assume it to be Majorana particle, which is compatible with all we know. You see that we create two neutrinos.
Let me make another example, possibly more standard. Consider again massive Majorana neutrino. Everybody knows (and if he/she doesn't can learn on that in Wiki) that by the neutrinoless double beta decay, a couple of electrons are formed.
My bottomline is
1) The renormalizable version of the standard model predicts that lepton number is conserved or if you want you do not produce net lepton number at any perturbative level. This is what you want to stress but as it is written it is not correct, see next point. What it is missing is a precise definition of what you are discussing "renormalizable standard model at perturbative level".
2) As it is written later in "Leptogenesis" this is not true at non perturbative level, since sphaleron can create lepton number. However this is not sufficient quantitatively to create enough leptons and realize the idea of Sakharov (it is not a principle problem). This is written already clearly and contradicts the part we are discussing: indeed it is stated "This means that the Standard Model is in principle able to provide a mechanism to create baryons and leptons"
3) But even worse, the renormalizable version of standard model is also inadequate to explain the fact that neutrinos are massive. If we include the first non-renormalizable operator, lepton number is violated immediately.
This is why I insist in recommending to remove the wrong (or misleading or irrelevant depending on what we discussing) statement that you recommend to maintain.
Best, Francesco
Hi Headbomb
please read "Sphaleron" on Wiki, it is considered part of the standard model.
Then it is evident to me that you "do feel that the article is not misleading on that point" otherwise we would not discuss. This is why you use the word contradiction is quotation marks while I use it without. However, if we can reach an agreement on the meaning of the word using the vocabulary, and then we read the text as it stands:
1) "in the currently accepted model for the elementary interactions, the so called Standard Model, it is not possible to create only "standalone" leptons"
2) "the Standard Model is in principle able to provide a mechanism to create baryons and leptons"
I believe we could agree.
I think the "physics" indication in the title is abundant. Are there any definitions of leptogenesis in other field? Correct me if I'm wrong.
Hhthoj ( talk) 04:22, 20 August 2019 (UTC)
The result of the move request was: page moved. ( non-admin closure) ~SS49~ {talk} 14:47, 9 June 2020 (UTC)
Leptogenesis (physics) → Leptogenesis – No reason for a dab page with two entries, one of which is only an alternative name. Create hatnote to Book of Jubilees per WP:TWODABS. ― Justin (koavf)❤ T☮ C☺ M☯ 01:15, 24 May 2020 (UTC) —Relisting. b uidh e 04:32, 2 June 2020 (UTC)