External leg amputation in conformal invariant three-point function

Abstract

Amputation of external legs is carried out explicitly for the conformal invariant three-point function involving two spinors and one vector field. Our results are consistent with the general result that amputing an external leg in a conformal invariant Green function replaces a field by its conformal partner in the Green function. A new star-triangle relation, involving two spinors and one vector field, is derived and used for the calculation.

Comments: 16 pages; last paragraph added in Sec. 10, presentation improved, to appear in Eur. Phys. J. C