Nucleon and Pion Form Factors in Different Forms of Relativistic Quantum Mechanics

Calculations of form factors in different forms of relativistic kinematics are presented. They involve the instant, front and point forms. In the two first cases, different kinematical conditions are considered while in the latter case, both a Dirac-inspired approach and a hyperplane-based one are incorporated in our study. Numerical results are presented for the pion form factors with emphasis on both the low and high Q**2 range. A new argument is presented, explaining why some approaches do considerably much better than other ones whenonly a single-particle current is considered.