Signals of extra gauge bosons and exotic leptons in SU(6)${}_L\otimes$U(1)${}_Y$

Abstract

We study some of the consequences of the SU(6)${}_L\otimes$U(1)${}_Y$ model of unification of electroweak interactions and families with a horizontal gauge group SU(2)${}_H$, paying special attention to processes with flavor changing neutral currents. We compute at tree level the decays $K^{+}⟶{\pi }^{+}{\mu }^{+}{e}^{-}$, $K_L^0⟶{\mu }^{+}{e}^{-}$ and ${\mu }^{-}⟶e^{-}\overline{{\nu }_e}{\nu }_{\mu }$ from which we obtain lower bounds for the mass of the horizontal gauge boson associated with FCNC. Finally we obtain limits on the mixing between ordinary and exotic charged leptons.