The charged Higgs boson is quite common in many new physics models. In this study we examine the potential of observing a heavy charged Higgs boson in its decay mode of top-quark and bottom-quark in the Type-II Two-Higgs-Doublet-Model. In this model,
the chirality structure of the coupling of charged Higgs boson to the top- and bottom-quark is very sensitive to the value of $tanbeta$. As the polarization of the top-quark can be measured experimentally from the top-quark decay products, one could make use of the top-quark polarization to determine the value of $tanbeta$. We preform a detailed analysis of measuring top-quark polarization in the production channels $gbto tH^-$ and $gbar{b}to bar{t}H^+$. We calculate the helicity amplitudes of the charged Higgs boson production and decay.Our calculation shows that the top-quark from the charged Higgs boson decay provides a good probe for measuring $tanbeta$, especially for the intermediate $tanbeta$ region. On the contrary, the top-quark produced in association with the charged Higgs boson cannot be used to measure $tanbeta$ because its polarization is highly contaminated by the $t$-channel kinematics.
Varying the Standard Model (SM) fermion Yukawa couplings universally by a generic positive scale factor ($F_{Yu}$), we study the phenomenological fit to the current available experimental results for the Higgs boson search at hadron colliders. We poi
nt out that the Higgs production cross section and its decay branching ratio to $gammagamma$ can be varied oppositely by $F_{Yu}$ to make their product almost invariant. Thus, our scenario and the SM Higgs are indistinguishable in the inclusive $Hto gammagamma$ channel. The current measurements on direct Yukawa coupling strength in the $Hto bbar{b}/tautau$ channel are not precise enough to fix the scale factor $F_{Yu}$. The most promising is the vector-boson-fusion channel in which the CMS has already observed possible suppression effect on the Yukawa couplings. Further more, the global $chi^2$ fit of the experimental data can get the optimal value by introducing a suppression factor $F_{Yu}sim1/2$ on the SM Yukawa couplings.
