The predictions of the $\sigma -\omega$ model for electromagnetic current are explored and found to be quite different from those given by the impulse approximation. In particular, large variations in the quasielastic electron scattering cross section are found depending upon the choice of the operator used for the current.

• Received 29 December 1983

DOI:https://doi.org/10.1103/PhysRevLett.53.895