Massive Quark-Gluon Scattering Amplitudes at Tree Level
arXiv:0710.1300 · doi:10.1103/PhysRevD.77.025011
Abstract
Results for four-, five-, and six-parton tree amplitudes for massive quark-antiquark scattering with gluons are calculated using the recursion relations of Britto, Cachazo, Feng, and Witten. The required diagrams are generated using shifts of the momenta of a pair of massless legs to complex values. Checks verifying the calculations are described, and a simple formula for the shifted spinors of an internal gluon is presented.
24 pages, 6 figures