Constraints on Extended Electroweak Theories

We obtain a model-independent lower bound on M(,R) of 300 GeV for a general class of SU(2)(,L) (CRTIMES) SU(2)(,R) (CRTIMES) U(1)(,B-L) left-right theories without any assumptions about the structure of the Cabibbo-Kobayashi-Maskawa matrices or the right-handed neutrino mass. Our result is also independent of Higgs-boson, dispersive, and W(,L)-W(,R) mixing contributions, and it holds for a range of bag constants, B. We also consider the minimal left-right symmetric electroweak model and characterize the range of allowable masses for the physical Higgs boson. We use two approaches: (1) We compute the lowest order boson-boson scattering amplitude and impose a unitarity constraint on the J = 0 partial -wave amplitude; (2) We compute the radiative corrections to the Higgs propagator and determine the range of Higgs masses for which the perturbation series converges. Both methods give upper bounds on the Higgs masses in terms of the gauge boson masses, and we discuss the theoretical connection. The generalizations of these constraints and their applicability in light of previous bounds is examined.