We show how the standard SU(2) × U(1) gauge model may be generalized to include several neutral intermediate vector bosons, without changing the predictions of the model for neutral-current neutrino interactions. The expanded gauge models involve at least one neutral intermediate vector boson which is lighter than the $Z^0\left(80\mathrm{} \mathrm{GeV}\right)$ of the standard model.

• Received 23 August 1977

DOI:https://doi.org/10.1103/PhysRevD.17.275