TECHNICOLOR WITH A MASSLESS SCALAR DOUBLET

We consider a minimal technicolor model in which the ordinary and tech nicolor sectors are coupled by a massless-scalar doublet. When technic olor interactions become strong, the resulting technicolor condensate not-only breaks the electroweak symmetry, but also causes the scalar t o develop a vacuum expectation value. With the appropriate choice of t he scalar's Yukawa couplings, fermion masses are generated,giving us t he conventional pattern of flavor symmetry breaking. Although no expli cit scalar mass term appears in the full Lagrangian of the model, the pseudoscalar states that remain in the low-energy effective theory gai n sufficient mass through technicolor interactions to evade detection. We show that this model does not generate unacceptably large flavor-c hanging neutral currents, and is consistent with the experimental cons traints on oblique electroweak radiative corrections. We determine the experimentally allowed region of the model's parameter space, and dis cuss the significance of a phenomenologically viable model that has no arbitrary dimensionful parameters. In terms of parameter counting, ou r model is the simplest possible extension of the standard model.