Top condensation from very massive strongly coupled gauge bosons

The Standard Model is extended minimally by making the U(1)Y field the unbroken subgroup of a bigger U(1)xU(1) gauge structure while the Higgs sector is omitted. If one of the original U(1)'s is strongly coupled then the residual effects of the strongly coupled massive component can lead to dynamical electroweak symmetry breaking by top condensation. An explicit renormalizable model with a scale of new physics in the multi TeV range is constructed and the top mass predictions as well as the phenomenology is discussed. It turns out that the effective lagrangian contains more than the usual Higgs sector which makes the scenario clearly distinguishable; in particular it is shown that for the strong coupling not all of the effects decouple as the heavy mass goes to infinity and there can be negative contributions to the ρ-parameter, thereby somewhat relaxing the stringent experimental upper bounds on the top mass. (orig.)