PHENOMENOLOGY OF THE TOP MASS IN REALISTIC EXTENDED TECHNICOLOR MODELS

Extended technicolor (ETC) theories typically require ETC gauge bosons lighter than of order 1 TeV, to perturbatively generate the t quark m ass. We point out that explicit models of t - b mass splitting also ty pically contain additional TeV scale ETC gauge bosons transforming in the adjoint of technicolor, leading to large weak-isospin-breaking eff ects observable in the rho parameter. Viable ETC models may thus requi re a lowest ETC scale of order 10 TeV, with relatively strong and fine ly tuned couplings to generate m(t). Such models do not generate obser vable corrections to the <Zb (b) over bar> vertex.