Family mass hierarchy from universal seesaw mechanism

The ‘‘universal seesaw mechanism,’’ which accounts for ${\mathrm{m}}_{\mathrm{e}}$,u,d≪${\mathrm{m}}_{\mathrm{W}}$, predicts ${\mathrm{m}}_{{\nu }_{\mathrm{L}}{\mathrm{m}}_{{\nu }_{\mathrm{R}}\mathrm{\approxeq }{\mathrm{m}}_{\mathrm{e}}^2}}$. Combined with an axial-vector symmetry principle, this mechanism allows for the coeexistence of heavy (≲${\mathrm{m}}_{\mathrm{W}}$) families without appeal to a hierarchy in Yukawa couplings and without introduction of additional mass scales. It then follows that (i) the physical right-handed heavy (light) ordinary fermions are mostly SU(2${)}_{\mathrm{R}}$ singlets (doublets), (ii) there is no analogous neutrino mass hierarchy, and (iii) ${\mathrm{m}}_{\mathrm{PQ}{\mathrm{m}}_{{\nu }_{\mathrm{L}}\mathrm{\approxeq }{\mathrm{m}}_{\mathrm{W}}^2}}$ sets the Peccei-Quinn mass scale.