arXiv:hep-ph/9502220v1 2 Feb 1995 Signals of extra gauge bosons and exotic leptons in SU(6) L ⊗U(1) Y Ricardo Gait´an-Lozano 1,2 , Albino Hern´ andez-Galeana 1,4 , Sergio A. Tom´ as 1 , William A. Ponce 1,3 and Arnulfo Zepeda 1 1- Departamento de F´ısica, Centro de Investigaci´on y de Estudios Avanzados del IPN A.P. 14–740, 07000 M´exico D.F., M´exico. 2- Departamento de F´ısica, Universidad Surcolombiana, A. A. 385, Neiva, Colombia. 3- Departamento de F´ısica, Universidad de Antioquia, A. A. 1226, Medell´ın, Colombia. 4-Escuela de Ciencias, UAEM. Unidad del Cerrillo, Piedras Blancas Instituto Literario 100, C.P 50000, Toluca Edo. M´exico. September 11, 2018 January 19, 1995 Abstract We study some of the consequences of the SU(6) L ⊗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 + −→ π + μ + e − , K 0 L −→ μ + e − and μ − −→ e − ¯ ν e ν μ 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. 1