Generalized unitarity method for unstable particles
arXiv:2111.11570 · doi:10.3390/universe9010028
Abstract
In theories with unstable particles, unitarity is satisfied by the inclusion of only stable states in unitarity sums. Hence unitarity cuts are not to be taken through unstable particles. This raises a challenge to the generalized unitarity method, whose aim is to reconstruct amplitudes by analyzing sets of unitarity cuts. Nevertheless, under some general physical conditions, and perhaps some methodological modifications, we prove that the method is still reliable for one-loop amplitudes containing resonances. We discuss some simple examples which illustrate these features.
arXiv comment23 pages, 2 figures; v2: Extensively revised version, many discussions have been extended, conclusions unchanged. Published version
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