Two scalar doublet models with softly broken symmetries

Abstract

A generalized two scalar doublet extension of the standard model is proposed, including a soft scalar term which explicitly breaks CP invariance and the discrete symmetry protecting against scalar mediated, flavour changing neutral currents. The allowed scalar spectrum in the model is discussed together with the top quark mass, based upon the adoption of renormalization group, quasi-fixed point values for the free hard couplings in the lagrangian. The radiative corrections arising from the new scalar sector are calculated and their phenomenological consequences commented upon. In the appendices a complete set of Feynman rules for the theory is given.