B−Las the fourth color within anSU(2)L×U(1)R×U(1)model

Quark-lepton correspondence and the corresponding interpretation of $B-L$ as the fourth color are combined in an $\mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_L\times \mathrm{U}{\mathrm{}\left(1\right)\mathrm{}}_R\times {\mathrm{U}}^{\prime }\mathrm{}\left(1\right)\mathrm{}$ electroweak model. The right-handed neutrino interactions are automatically suppressed and the standard model is recovered up to a desirable first-order fine structure. A fundamental distinction is established between the real Weinberg angle and its effective (measured) values. For neutrino interactions, our predictions are in general of the Weinberg-Salam (WS) type, only with the effective replacement ${{sin}^2\theta }_W\to {{sin}^2\theta }_W^{\mathrm{eff}}$ such that (a) ${{sin}^2\theta }_W^{\mathrm{eff}}\left(\mathrm{purely}\mathrm{leptonic}\mathrm{processes}\right)>\mathrm{}{{sin}^2\theta }_W^{\mathrm{eff}}\left(\nu q \mathrm{scattering}\right)$, and (b) for ${{sin}^2\theta }_W=\frac{1}{4}$ one can still have a lower value for the weighted average of ${{sin}^2\theta }_W^{\mathrm{eff}}$. Our expressions for the asymmetry parameter in electron-induced reactions agree with those of the WS model up to a second-order term. The additional neutral gauge boson is expected to be only 1 order of magnitude heavier than $W^{\pm }$. We argue that the present neutral-current experimental data are not capable of distinguishing between the standard and the present models. Finally we discuss the possibility of embedding our model in a unified gauge theory, showing that only spinorial $\mathrm{SO}\mathrm{}(4k+2)\mathrm{}$ theories are available for this purpose.