Vector-like Strong Coupling Theory with Small S and T Parameters

Abstract

We discuss a mechanism which can reduce the S and T parameters in dynamical electroweak symmetry breaking scenario. It is interesting that not only T but also S parameters can be made small even if large isospin violation exists, which can realize the heavy top quark. The point is that if massive vector-like fermions, which have gauge invariant masses, can condense and break the electroweak symmetry, the S and T parameters can be small because of the decoupling theorem. Moreover, the model predicts a heavier Higgs boson, which may be found in LHC. The presentation basically follows the original papers.