β Scribed by T.L Trueman; G.C Wick
No coin nor oath required. For personal study only.
Crossing relations for helicity amplitudes for particles of arbitrary spin are formulated without recourse to the introduction of scalar amplitudes. The basic assumption is that the amplitudes are simply related by analytic continuation;
the path of continuation is carefully specified. The relations are given a simple geometrical interpretation.
The relation between TN + wN and ?rr + N?? obtained in this way agrees with that obtained by direct elimination of scalar amplitudes. * Work performed under the auspices of the U. S. Atomic Energy Commission. 1 We are indebted to Prof. M. Goldberger for repeatedly drawing our attention to this question.
π SIMILAR VOLUMES
We discuss the calculation of two-loop helicity amplitudes for quark-quark scattering in QCD and four-gluino scattering in N = 1 supersymmetric Yang-Mills theory. We study the dependence of the results on different variants of dimensional regularization. In particular, we consider the 't Hooft-Veltm