Relativistic effects in the electromagnetic current at GeV energies

We employ a recent approach to the nonrelativistic reduction of the electromagnetic current operator in calculations of electronuclear reactions. In contrast to the traditional scheme, where approximations are made for the transferred momentum, transferred energy, and initial momentum of the struck nucleon in obtaining an on-shell inspired form for the current, we treat the problem exactly for the transferred energy and transferred momentum. We calculate response functions for the reaction ${}^2\mathrm{H}{(e,e}^{\prime }p)n$ at CEBAF (TJNAF) energies and find large relativistic corrections. We also show that in plane wave impulse approximation, it is always possible to use the full operator, and we present a comparison of such a limiting case with the results incorporating relativistic effects to the first order in the initial momentum of the struck nucleon.