Dynamical electroweak symmetry breaking due tostrong Yukawa interactions

摘要

We present a new mechanism for electroweak symmetry breaking (EWSB)based on a strong Yukawa dynamics. We consider an SU (2)_Lx U(1) _Ygaugeinvariant model endowed with the usual Standard Model fermion multipletsand with two massive scalar doublets. We show that, unlike in the StandardModel, EWSB is possible even with vanishing vacuum expectation values ofthe scalars. Such EWSB is achieved dynamically by means of the (presumablystrong) Yukawa couplings and manifests itself by the emergence of fermionand gauge boson masses and scalar mass splittings, which are expressed ina closed form in terms of the fermion and scalar proper self-energies. The`would-be' Nambu–Goldstone bosons are shown to be composites of both thefermions and the scalars. We demonstrate that the simplest version of the modelis compatible with basic experimental constraints.