Physical Implications of a Vector-like Extension of the Standard Model

Abstract

Physical implications of a vector-like extension of the standard model for heavier quarks and leptons with $SU(2)\times U(1)$ gauge symmetry and only one Higgs doublet are discussed. This scheme incorporates infinitely many fermions, and the chiral structure is realized by a non-vanishing analytic index of mass matrices. The model is perturbatively well controllable, and the physical Higgs particle generally mediates leptonic as well as quark flavor-changing processes at a rate below the present experimental limit. This model illustrates a general feature of models where some of the fermion masses are of non-Higgs origin.

Comments: Some references are added. 5 pages. Talk presented at KOSEF-JSPS Winter School on Recent Developments in Particle and Nuclear Theory, Seoul, Korea, February 21-28,1996 (To be published in Supplement of Journal of Korean Physical Society)