We describe an SU(3) ⊗ U(1) gauge theory of weak and electromagnetic interactions and study its experimental implications. In this theory all nonsinglet fermions are assigned to triplet representations of SU(3). The theory satisfactorily accounts for the trimuon events recently observed in neutrino reactions. Furthermore, the model naturally ensures quark-lepton and $e-\mu$ universality, absence of right-handed currents in $\beta$ and $\mu$ decay, and absence of $s-d$ neutral currents to order $G_F\alpha$. Various discrete symmetries play an important role in maintaining these properties. The model allows for $\mu$- and $e$-type lepton-number nonconservation at a naturally strongly suppressed level. The weak contributions to the anomalous magnetic moments of the electron and muon are calculated and shown to be in accord with experimental bounds. The predictions of the model for most neutral-current reactions are in good agreement with the data on these processes. Other features of the theory include the prediction of an absolutely stable massive neutral lepton, the absence of a sizable high-$y$ anomaly in antineutrino charged-current reactions, and the absence of large parity violation in heavy atoms.

• Received 5 October 1977

DOI:https://doi.org/10.1103/PhysRevD.17.2410