New approach to the electron-muon mass ratio

Abstract

A class of models is devised which, while respecting electron-muon universality in the Lagrangian, results naturally in a small value of $\frac{{m}_{e}}{{m}_{\ensuremath{\mu}}}$, and which does not involve the introduction of exotic new gauge interactions. [The gauge group is SU(2) \ifmmode\times\else\texttimes\fi{} 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 $\frac{{m}_{e}}{{m}_{\ensuremath{\mu}}}$ depends upon the masses of these leptons.