Abstract We discuss possible parallel textures of the Yukawa coupling matrices in the general two-Higgsdoublet model (2HDM). In those textures the flavor changing neutral currents are naturally suppressed. Motivated by a phenomenologically successful texture with four texture zeros in the standard model, we propose a predictive ansatz for the Yukawa coupling matrices with the same texture in th...

A study of Rb and Rc is presented in the context of a Two Higgs Doublet Model (2HDM) with avor changing scalar currents (FCSC). Implications of the model for the -parameter and for b ! s are also considered. The experimental data on Rb places stringent constraints on the model parameters. The con guration of the model needed to account for Rb is found to be irreconcilable with constraints from ...

The sensitivity to a light Higgs boson in the general 2HDM (II), with a mass below 40 GeV, is estimated for an future ee linear collider operating with very high luminosity at the Z peak (GigaZ). We consider a possible Higgs boson production via the Bjorken process, the (hA) pair production, the Yukawa process Z → bb̄h(A),→ τ τ̄h(A), and the decay Z→h(A) + γ. Although the discovery potential is c...

We study an extended 2 Higgs doublet model (2HDM) in which the Standard Model (SM) Yukawa interactions are forbidden due to a global $U(1{)}^{\ensuremath{'}}$ symmetry, but may arise via mixing with vectorlike families. In this model, hierarchical structure of couplings quarks and leptons SM arises from heavy masses fourth fifth Within we consider various nonstandard contributions electron muon...