IDMclean Posted February 18, 2005 Report Share Posted February 18, 2005 What could be said then about the Photon Annihilation of Gamma rays to produce an Electron and a Positron? Link to comment Share on other sites More sharing options...
Qfwfq Posted February 21, 2005 Report Share Posted February 21, 2005 The single QED vertex could represent the process: gamma ---> e- e+ but this can't conserve the energy-momentum 4-vector. This means either there must be two gammas, or another massive charged object involved. Sure enough, when e- e+ annihilate in free space, they give a pair of photons and not a single one. Is this what you were asking about KAC? Or were you hinting something about virtual photons, which may have a non-zero dispersion? I was only making a point, perhaps in a rather subtle way, about basic SR to Mr. Rao and others who are optimistic about superluminal causality propagation. Link to comment Share on other sites More sharing options...
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