Lepton--hadron symmetry breaking and the Cabibbo rotation

It is shown that spontaneous breakdown of gauge-invariant SU(2)_L×U(1) lepton-hadron theories can induce hadron chiral-symmetry-breaking terms consistent with parity and hypercharge conservation and with earlier results of the (3,3*) + (3*,3) model. The theories limit to SU(2) × SU(2) for hadrons, zero Cabibbo angle, and no isospin-breaking term (u₃) when the cross coupling between leptons and hadrons is removed or when the SU(2)_L×U(1) gauge symmetry is realized without spontaneous breakdown. The Cabibbo angle is not constrained.