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Sep2-10, 04:21 AM
humanino's Avatar
P: 2,828
What about small momentum divergences?

Those small momentum divergences may be real : for instance, there is really an infinity of zero angle zero energy photons along an electron's line. One has to integrate the cross section over finite angle and finite energy to get a finite result. This kind of divergence is also at the root of the concept of "jet" in QCD.