New and improved quark-lepton symmetric models

We show how the use of a see-saw mechanism based on a 3 × 3 neutrino mass matrix texture can considerably simplify Higgs sectors for quark-lepton symmetric models (and for Standard Model extensions generally). The main theory we discuss also incorporaties a previously considered scenario whereby the charged lepton of a particular generation is necessarily less massive than the corresponding charge +23 quark, provided intergenerational mixing is small.