2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/199352Results 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 figuresHigh Energy Physics - Phenomenologytext