A Truly Minimal Left-Right Symmetric Extension of the Standard Model

By invoking the existence of a general custodial O(2) symmetry, a minimal Left-Right symmetric model based on the gauge group G=SU(2)L SU(2)R U(1)BL is shown to require the existence of only two physical Higgs bosons. The lighter Higgs is predicted to have a small mass which could be evaluated by standard perturbation theory. The fermionic mass matrices are recovered by insertion of ad hoc fermion-Higgs interactions. The model is shown to be undistinguishable from the standard model at the currently reachable energies.