Need for Two Vectorlike Families in SUSY Composite Models

Abstract

Within the context of a viable and economical SUSY preon model, two vector--like families $Q_{L,R}=(U,D,N,E{)}_{L,R}$ and $Q_{L,R}^{\prime }=(U^{\prime },D^{\prime },N^{\prime },E^{\prime }{)}_{L,R}$ with masses of order 1 TeV, one of which is a doublet of $SU(2{)}_L$ and the other a doublet of $SU(2{)}_R$, have been predicted to exist together with the three observed chiral families. The existence of these two vector--like families turns out to be crucial especially for an explanation of the inter--family mass--hierarchy and therefore for the SUSY preon model itself. This paper is devoted to a detailed study of the expected masses, mixings and decay modes of the vector--like fermions. Including QCD renormalization--effects, the masses of the vector--like quarks are expected to lie in the range of 500 GeV to about 2.5 TeV, while those of the vector--like leptons are expected to be in the range of 200 GeV to 1 TeV.

Comments: 6 pages, LaTeX, no macros needed