Effective boost and 'point-form' approach

Triangle Feynman diagrams can be considered as describing the form factors of states bound by a 'zero-range' interaction. These form factors are calculated for scalar particles and compared to point-form and non-relativistic results. By examining the expressions of the complete calculation in different frames, an effective boost transformation is obtained. It is compared to the relativistic kinematical one underlying the present point-form calculations, and to the Galilean one. (authors)