A systematic study is made of nonstandard fermion multiplets in left-right-symmetric models with the gauge group ${\mathrm{SU}\mathrm{}\left(3\right)\mathrm{}}_C\otimes {\mathrm{SU}\mathrm{}\left(2\right)\mathrm{}}_L\otimes {\mathrm{SU}\mathrm{}\left(2\right)\mathrm{}}_R\otimes {\mathrm{U}\mathrm{}\left(1\right)\mathrm{}}_{B-L}$. Constraints from gauge anomaly cancellation and invariance of Yukawa coupling terms are used to define interesting classes of exotic fermions. We identify the standard quark-lepton spectrum of left-right-symmetric models as the simplest member of an infinite class. The phenomenological implications of the next simplest member of this class are then studied. We also consider classes of exotic fermions which may couple to the standard fermions through doublet Higgs bosons. We then show that some of these exotics may be used to induce a generalized universal seesaw mechanism.

• Received 27 November 1991

DOI:https://doi.org/10.1103/PhysRevD.45.4261