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We apply the on-shell tree-level recursion relations of Britto, Cachazo, Feng and Witten to a variety of processes involving internal and external massive particles with spin. We show how to construct multi-vector boson currents where one or more off-shell vector bosons couples to a quark pair and number of gluons. We give compact results for single vector(More)
We derive general tree-level recursion relations for amplitudes which include massive propagating particles. As an illustration, we apply these recursion relations to scattering amplitudes of gluons coupled to massive scalars. We provide new results for all amplitudes with a pair of scalars and n ≤ 4 gluons. These amplitudes can be used as building blocks(More)
We present a method for the direct extraction of rational contributions to one-loop scattering amplitudes, missed by standard four-dimensional unitarity techniques. Working in D = 4 − 2ǫ dimensions, we interpret the dependence on the additional dimensions as equivalent to introducing an internal mass. We combine this with the use of generalised unitarity to(More)
We consider a Higgs boson coupled to gluons via the five-dimensional effective operator HtrG µν G µν produced by considering the heavy top quark limit of the one-loop coupling of Higgs and gluons in the standard model. We treat H as the real part of a complex field φ that couples to the selfdual gluon field strengths and compute the one-loop corrections to(More)
We consider one-loop amplitudes of a Higgs boson coupled to gluons in the limit of a large top quark mass. We treat the Higgs as the real part of a complex field φ that couples to the self-dual field strengths and compute the one-loop corrections to the φ-NMHV amplitude, which contains one gluon of positive helicity whilst the remaining three have negative(More)