Boundary contributions using fermion pair deformation
Bo Feng, Zhibai Zhang
Journal of High Energy Physics
Continuing the study of boundary BCFW recursion relation of tree level amplitudes initiated in Feng:2009ei, we consider boundary contributions coming from fermion pair deformation. We present the general strategy for these boundary contributions and demonstrate calculations using two examples, i.e, the standard QCD and deformed QCD with anomalous magnetic momentum coupling. As a by-product, we have extended BCFW recursion relation to off-shell gluon current, where because off-shell gluon
... is not gauge invariant, a new feature must be cooperated.