Symmetries of higher-spin fields and the electromagnetic N-N(1680) form factors

We study the Q^2-evolution of the form factors (FFs) for the nucleon-to-N(1680) transition in the framework of an effective field theory. To this end, the intrinsic symmetries of the spin-5/2 Rarita-Schwinger (RS) fields are analyzed, and a Lagrangian of the electromagnetic N-N(1680) interactions is constructed. The Lagrangian preserves all the intrinsic symmetries of the spin-5/2 field–point and gauge invariance–and does not involve lower-spin components of the reducible RS field. Besides, the symmetries postulate the definitions of the Lagrangian FFs. These FFs are modeled as dispersionlike expansions in a vector-meson–dominance model. A good agreement with the experimental data is achieved.