Publication details for Simon BadgerBadger, Simon, Brønnum-Hansen, Christian, Buciuni, Francesco & O’Connell, Donal (2017). A unitarity compatible approach to one-loop amplitudes with massive fermions. Journal of High Energy Physics 2017(6): 141.
- Publication type: Journal Article
- ISSN/ISBN: 1029-8479 (electronic)
- DOI: 10.1007/JHEP06(2017)141
- Further publication details on publisher web site
- Durham Research Online (DRO) - may include full text
Author(s) from Durham
We explain how one-loop amplitudes with massive fermions can be computed using only on-shell information. We first use the spinor-helicity formalism in six dimensions to perform generalised unitarity cuts in d dimensions. We then show that divergent wave-function cuts can be avoided, and the remaining ambiguities in the renormalised amplitudes can be fixed, by matching to universal infrared poles in 4 − 2ϵ dimensions and ultraviolet poles in 6 − 2ϵ dimensions. In the latter case we construct an effective Lagrangian in six dimensions and reduce the additional constraint to an on-shell tree-level computation.