In the simplest examples of models with a discrete quark-lepton symmetry, an electroweak symmetry-breaking sector with more than one Higgs doublet is necessary to obtain the correct mass relations between quarks and leptons. A two Higgs doublet model version has flavor-nonconserving Yukawa couplings, which are proportional to the masses of the quark-lepton symmetric partners of the fermions. We describe how flavor-changing leptonic decays can occur, with branching ratios not far beyond those currently measurable, enabling investigation of the phenomenology of such models.

• Received 11 March 1994

DOI:https://doi.org/10.1103/PhysRevD.51.285