Talk:Annihilation

message: And how close together do they have to be for annihilation to happen?68.6.85.167 10:21, 9 May 2006 (UTC)
replies: text: Due to quantum uncertainty, such a question may not be meaningful. The probability per unit time will depend on the overlap of the wavefunctions of the two particles. Something on the order of the Compton wavelength, maybe? -- Xerxes 16:22, 9 May 2006 (UTC)
thread_title: Question

message: What's the deal with this line:
*"However, in quantum field theory this process is allowed as an intermediate quantum state for times short enough that the violation of energy conservation can be accommodated by the uncertainty principle."
If by intermediate processes in quantum field theory we mean Feynman diagram vertices, then no, every vertex conserves energy. All that's temporarily violated is the energy-momentum relations of free particles. And if we're not talking about Feynman diagrams, then what does this even mean? Melchoir 07:23, 3 July 2006 (UTC)
thread_title:  Energy nonconservation? 

message: Is it true that the exact reverse of annihilation is involved in the proton-proton chain reaction?--67.10.200.101 00:20, 3 November 2006 (UTC)
thread_title:  The Proton-Proton Chain Reaction 

message: I have firefox and I can't see the picture of a positron and an electron annihilating into a photon. I thought I should tell all of you, Jeffrey.Kleykamp 23:22, 12 May 2007 (UTC)
thread_title: I can't see the picture

message: This article's great, but I feel there should be another article created to discuss NONE physics related annihilation, such as apocalypse.  82.18.44.72 (talk) 23:59, 29 March 2008 (UTC)
thread_title:  scope 

message: After much looking, I can't seem to discover the theory behind why antimatter and matter (on contact) annihilate one another. Is it something that is simply unknown, or is it just an omission? 79.71.190.207 (talk) 22:13, 17 February 2009 (UTC)
replies: text: The particles are simply opposite. They cancel each other out, and… yeah. See the rest of the article for a more detailed background… 24.130.10.143 (talk) 02:48, 21 May 2010 (UTC)
thread_title: Why?

message: Forgive a non-physicist for lack of knowledge here, but could someone tell me roughly how much energy you get out of particle Annihilation? Hypothetically speaking (particularly in Science Fiction) if a fellow had a heap of Matter and a heap of Anti-Matter and he put the two together, what would he get? Enough power to make his car run, or blow up the earth? If you had an equal mass of, say, Anti-Hydrogen as you did Plutonium, which could you get more energy out of? I know in practice this is pretty much useless to scientists because Anti Matter doesn't just happen to be sitting around in piles, but I've seen it used in Science Fiction and I'm quite curious as to how much energy you get out of it. For that matter, the article could go a section on examples in fiction. 43.244.33.36 (talk) 13:29, 7 March 2009 (UTC)
thread_title:  Amount of energy? 

message: Sorry, but I'm not really knowledgeable in this field. But I came across this when studying for exams :) 
It states that when an electron and an anti-electron undergo mutual annihilation, the Lepton number does NOT have to be conserved. Thanks for reading!
Krazywrath~ (talk) 02:51, 12 May 2009 (UTC)
thread_title:  Lepton Number not conserved?? 

message: The article includes the summary of Electron-positron annihilation taken from the relevant main article, but the summary of Proton antiproton annihilation from its main article is missing.  — Preceding unsigned comment added by Rhsimard (talk • contribs) 22:41, 19 March 2011 (UTC)
thread_title:  Article stops short 

message: I just corrected a factual error (that was introduced and went unnoticed quite some time), but in any case the paragraph on electron-positron annihilation would be a worthwhile target for a rewrite. I find the complete lack of any serious reference even more grave (I myself am not too comfortable in quantum electrodynamics to be able to do that). Seattle Jörg (talk) 13:17, 1 March 2013 (UTC)
thread_title:  References? 

message: Most of the pages on annihilation refer to the products of annihilation as gamma rays. While this is a common statement, it is not strictly true. By most definitions, a gamma ray originates from the nucleus, which is not the case of annihilation photons. It is unquestionably correct to refer to the product as a photon; gamma is a term of convenience and in this context is controversial at best. There is a small section on the X-ray#Gamma_rays article describing the difficulty of distinguishing between types of photon radiation; perhaps it is worthwhile to add an explanation of this distinction in the article? 
Cjweber (talk) 00:51, 11 January 2020 (UTC)
thread_title:  Photon/gamma ray distinction 

message: I'm no expert, but afaik it's generally the convention for Feynman diagrams to use the X axis for time and the Y axis for space, rather than vice versa. This allows the interaction to be "read" from left to right, rather than from bottom to top. The diagram here is technically correct, in that the interaction it shows is correct, but the fact its axes are reversed makes it a little confusing/counterintuitive for beginners. A possible replacement would be something like this:
Like I said, I'm def no expert here, so do lmk if I'm missing something obvious! Tpth (talk) 04:33, 22 May 2020 (UTC)
thread_title:  Feynman diagram axes reversed?