Relativistic effects in bound-state form factors

Abstract

The formalism for bound-state form factors in a three-dimensional relativistic theory is used to expose the theoretical limitations of recent work on meson exchange currents. The pair excitation and recoil emission currents used in phenomenological calculations are found to have little theoretical support. The constraints imposed by the Ward identity are examined and the singularity structure of the form factor in relativistic and nonrelativistic theories is compared.