NovelCP-violating effects inBdecays from a charged Higgs boson in a two-Higgs-doublet model for the top quark

We explore charged-Higgs $\mathrm{CP}$-violating effects in a specific type III two-Higgs-doublet model which is theoretically attractive as it accommodates the large mass of the top quark in a natural fashion. Two new $\mathrm{CP}$-violating phases arise from the right-handed up quark sector. We consider $\mathrm{CP}$ violation in both neutral and charged B decays. Some of the important findings are as follows. (1) Large direct-$\mathrm{CP}$ asymmetry is found to be possible for $B^{\pm }\to \psi {/JK}^{\pm }.$ (2) A sizable $D\overline{D}$ mixing effect at the percent level is found to be admissible despite the stringent constraints from the data on $K\overline{K}$ mixing, $\overrightarrow{b}s\gamma$ and $B^{-}\to \tau \overline{\nu }$ decays. (3) A simple but distinctive $\mathrm{CP}$ asymmetry pattern emerges in decays of $B_d$ and $B_s$ mesons, including $B_d\to \psi /J$ $K_S,$ $D^{+}{D}^{-},$ and $B_s\to D_s^{+}{D}_s^{-},$ $\psi$ $\eta /{\eta }^{\prime },$ $\psi /J$ $K_S.$ (4) The effect of $D\overline{D}$ mixing on the $\mathrm{CP}$ asymmetry in $B^{\pm }\to D/\overline{D}{K}^{\pm }$ and on the extraction of the angle γ of the unitarity triangle from such decays can be significant.