Adding a horizontal gauge symmetry to the Weinberg-Salam model: An eight-quark model

Abstract

An eight-quark model is constructed. It incorporates a horizontal SU(2) gauge symmetry in addition to the $\mathrm{SU}{(2)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1)$ gauge symmetry of Weinberg and Salam. Cabibbo universality is reproduced. $\mathrm{CP}$ violation can also be obtained. Experimental data on the ${K}_{L}\ensuremath{-}{K}_{S}$ mass difference and neutral-current experiments are used to estimate the lower bounds on the masses of the horizontal SU(2) gauge bosons; the values turn out to be less than ${\ensuremath{\alpha}}^{\ensuremath{-}\frac{1}{2}}{M}_{W}$. No mixing exists between the horizontal gauge fields and the $\mathrm{SU}{(2)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1)$ gauge fields; the Weinberg-Salam model of weak and electromagnetic interactions is preserved perfectly.