content_image/366137.jpg content_image/366139.jpg
with 

<img src='content_image/366137.jpg'>

where we have neglected the small contributions from light leptons. Consequently, the contour for R ¯ B → Dτ ¯ ν$_{τ}$ as a function of η$_{b}$/m$_{H}$ ± and φ τ b is displayed in Fig. 5. We have demonstrated that B ( B − → Dτ ¯ ν$_{τ}$ ) is also sensitive to the effects of H $^{±}$. 

<img src='content_image/366139.jpg'>

In summary, we find a new scheme for Yukawa couplings in general THDM without imposing symmetry. The scheme not only can avoid FCNC at tree level but also provides a novel couplings of charged Higgs to fermions. With the constraint of b → sγ , we find that the violation of lepton universality can be simplified to be the flavor dependent CP violating phase factor, φ ℓ $_{D$_{j}$}$. Unlike conventional type-II THDM, the new H $^{±}$-mediated effects have the specialties: (a) the influence on Γ( K ± e $_{2}$) / Γ( K ± µ $_{2}$) cannot be eliminated, (b) the decay constant of D$_{s}$ could be enhanced, and (c) enhancement of branching ratio for B + → τ $^{+}$ν could be accomplished. 

## Acknowledgments 

This work is supported by the National Science Council of R.O.C. under Grant Nos. 

