Abstract
Unitarity cuts diverge in the channel of a single massive external fermion. We propose an off-shell continuation of the momentum that allows a finite evaluation of the unitarity cuts. If the cut is taken with complete amplitudes on each side, our continuation and expansion around the on-shell configuration produces the finite contribution to the bubble coefficient. Finite parts in the expansion of the external leg counterterms must be included explicitly as well.
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Britto, R., Mirabella, E. External leg corrections in the unitarity method. J. High Energ. Phys. 2012, 45 (2012). https://doi.org/10.1007/JHEP01(2012)045
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DOI: https://doi.org/10.1007/JHEP01(2012)045