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pierce15
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Sorry if this is a trivial question; I don't know very much about particle physics.
ChrisVer said:Yes neutrinos+antineutrinos annihilate, as all the other particles+antiparticles... I don't think they can annihilate by photon emission but they can by [itex]Z^{0}[/itex]...
piercebeatz said:Is there some kind of equation applicable to this scenario?
Matterwave said:Yes, it would the sum of all Feynman diagrams with ##\nu_e \bar{\nu}_e\rightarrow Z^0 Z^0##
Or perhaps ##\nu_e \bar{\nu}_e\rightarrow \gamma\gamma##
Essentially...and perhaps other products...But...these diagrams are highly complicated and non-trivial...I wouldn't know how to evaluate them. I can only give some guesses.
ChrisVer said:https://www.physicsforums.com/showthread.php?t=622173
although as stated I cannot understand post #7...
mass doesn't mean that you can have annihilation to photons if your charge (vertex coupling) is zero... Or the poster meant something else...
piercebeatz said:Maybe this is pushing a little too far, but does whether a neutrino and an antineutrino annihilate have any significance in our view of the universe? i.e. if we experimentally showed either that this reaction forms photons/an electron-positron pair or that it doesn't occur at all, would this have any implications in particle physics?
phinds said:For practical considerations, see post #2
The Standard Model predicts it can happen, so if it doesn't happen, that would be a serious challenge to the Standard Model.piercebeatz said:if we experimentally showed either that this reaction forms photons/an electron-positron pair or that it doesn't occur at all, would this have any implications in particle physics?
In fact, some of the most stringent tests of the Standard Model are those reactions that are extremely unlikely, and consequently extremely rare.piercebeatz said:Just because it's unlikely doesn't mean it isn't possible or unworthy of consideration.
I was not suggesting otherwise. I think we're talking at cross purposes. I was commenting on the practical significance to everyday life which sort of addressed the first part of your question, not the second part.piercebeatz said:Just because it's unlikely doesn't mean it's impossible or unworthy of consideration...
ChrisVer said:Of course, if the OP checks the other thread I posted, he'll find that people there said the process of neutrino-antineutrino annihilation is not yet observed, because it's very small... neutrinos interact hardly with matter, just imagine expecting two of them to interact with each other hehehe.
In some circumstances it can be important. http://www.researchgate.net/publication/234421034_Neutrino_annihilation_in_Type_II_supernovae says:ChrisVer said:neutrinos interact hardly with matter, just imagine expecting two of them to interact with each other hehehe.
ABSTRACT: Neutrino-antineutrino annihilation into electrons and positrons can
deposit more than 10 to the 51st ergs above the neutrino-sphere of a
type II supernova.
Granted, it's a weak interaction, but there are several points to note... first of all the cross-section of the lowest order Feynman diagram for neutrino scattering is G2s - it grows rapidly with energy. The traditional "light-year of lead" remark is, I'm afraid, popsci woo. :shy: It pertains to low energy neutrinos, and does not take the energy dependence into account.ChrisVer said:neutrinos interact hardly with matter, just imagine expecting two of them to interact with each other hehehe.
Neutrinos have no EM charge... And so they cannot generate photons? Having Weak charge only... They can only generate Weak bosons?ChrisVer said:Yes neutrinos+antineutrinos annihilate, as all the other particles+antiparticles... I don't think they can annihilate by photon emission but they can by [itex]Z^{0}[/itex]...
TEFLing said:Neutrinos have no EM charge... And so they cannot generate photons? Having Weak charge only... They can only generate Weak bosons?
mfb said:Assuming this is also true for our off-shell Z.
ChrisVer said:I think the Z--->gamma gamma by a triangle fermion loop doesn't work...
Neutrinos and antineutrinos are subatomic particles that have no electric charge and very little mass. They are produced in nuclear reactions, radioactive decay, and high-energy collisions.
Annihilation is a process in which a particle and its antiparticle collide and are converted into other particles or energy. In the case of neutrinos and antineutrinos, they can annihilate and produce other particles such as electrons and positrons.
Neutrinos and antineutrinos can only annihilate if they have the same energy and opposite spin. When they collide, they can produce a W boson which then decays into other particles, or they can directly produce an electron and a positron.
The annihilation of neutrinos and antineutrinos is important because it is a rare process that can provide valuable information about the properties of these particles. It can also help scientists understand the early universe and the balance between matter and antimatter.
Yes, we can observe the annihilation of neutrinos and antineutrinos through experiments such as the Large Hadron Collider (LHC) and IceCube. These experiments can detect the particles produced from the annihilation and provide evidence for this process.