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snorkack
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Positronium annihilation opportunities are strongly restricted by the requirement to conserve spin. The spin of a photon is 1; and for some reasons two photons are completely unable to have spins in different directions. They can only have parallel spins (total 2) or antiparallel spins (total 0) - never 1, and this prevents a positron with spin parallel to an electron from annihilating to 2 photons. Only 3 photons are possible (also 5 or larger odd numbers) which is very much slower process.
Now how about antiproton?
The problem here is that antiprotons are said to annihilate normally into pions - but pion spin is 0.
No matter how many pions are produced, whether 3, 4, 5 or more, no combination of pions can possibly handle the combined spin of proton and antiproton with parallel spins.
So is such annihilation possible?
Now how about antiproton?
The problem here is that antiprotons are said to annihilate normally into pions - but pion spin is 0.
No matter how many pions are produced, whether 3, 4, 5 or more, no combination of pions can possibly handle the combined spin of proton and antiproton with parallel spins.
So is such annihilation possible?