Leptonic Electroweak Model with No Ad HocParity-Breaking Prescriptions and No HiggsParticles

Abstract

The leptonic sector of the standard model is revisited in the light of a recentstrictly covariant, generalized quantum field formalism that naturally accountsfor the “maximal P-violation” effect without needing to postulate any true failureof P mirror symmetry. In full accordance with neutrino-antineutrinophenomenology, such an approach strictly predicts the nonexistence ofright-handed (massless) neutrinos and left-handed (massless) antineutrinos: itspontaneously leads to a universal theory of a merely left-handed massless fermionand a merely right-handed corresponding antifermion, where such particles maynow be P-symmetrically interpreted as just two pseudoscalar-charge conjugatedobjects being the ordinary mirror image of each other. On these grounds, a weakisospin of pseudoscalar components is introduced, which can alternately yield adouble—either SU(2)L (leptonic) or SU(2)R (antileptonic)—variety of SU(2)representations, each with its own weak-hypercharge variety. Hence two equallyallowable SU(2) ⊗ U(1) massless gauge schemes are covariantly built, the formerincluding (right-handed) antileptons as SU(2)L-singlets and the latter including(left-handed) leptons as SU(2)R-singlets. In either alternative scheme, the“charged” lepton and antilepton can but bear as yet an electric charge quiteindefinite in sign: they can really be made two electric charge conjugatedeigenstates (with opposite eigenvalues) only by acquiring mass and turning intoDirac particles. Herein the charged-lepton mass appearance no longer looks likejust an external “accident” connected with a hypothetical coupling to a Higgsboson; it rather becomes an essential internal requirement for the generation ofthe leptonic electromagnetic gauge coupling. A suitable effective mechanism ofmass production is shown to be provided by simply introducing a net “vacuum”Higgs isodoublet field merely including the three Goldstone freedom degreesand not including the Higgs-boson excitation: such a field still has a nonzerovacuum expectation value and still generates SSB and Weinberg mixing, thoughwith the only further (internal) effect of giving mass to both the intermediatevector bosons and the charged lepton (antilepton). Two equivalent covariantelectroweak final schemes for either leptons or antileptons are thus obtainedwhich contain no Higgs-boson couplings and can all the same reproduce thewell-established standard results. Either scheme may be said not to be P-symmetricbut for the presence of the neutral weak current coupling, as a mere outcome ofthe mixed (and not purely pseudoscalar) nature of the “electroweak” effectivecharge therein involved.