New approach to the electron-muon mass ratio. [Su(2) xU(1) gauge model, Weinberg-Salam model extension, discrete, symmetry, heavy leptons]
A class of models is devised which, while respecting electron-muon universality in the Lagrangian, results naturally in a small value of /m/sub e//m/sub ..mu../, and which does not involve the introduction of exotic new gauge interactions. (The gauge group is SU(2) x U(1) and the model is a relatively simple extension of the Weinberg-Salam model.) This is achieved by repeated applications of discrete symmetry. The model requires the existence of heavy leptons, and the precise value of m/sub e//m/sub ..mu../ depends upon the masses of these leptons.