Form factors of hadronic systems in various forms of relativistic quantum mechanics

B. Desplanques

Published 2004-05-21Version 1

The form factor of hadronic systems in various forms of relativistic quantum mechanics is considered. Motivated by the agreement of the nucleon ``point-form'' results with experiment, results for a toy model corresponding to the simplest Feynman diagram are first presented. These ones include the results for this diagram, which plays the role of an experiment, for the front-form and instant-form in standard kinematics (q^+=0 and Breit frame), but also in unconventional kinematics and finally a Dirac's point-form inspired approach. Results for an earlier ``point-form'' approach are reminded. Results are also presented for the pion charge form factor. Conclusions as for the efficiency of various approaches are given.