Study of B0-->J/Psi D(*) and etac D(*) in Perturbative QCD

Motivated by recent interest in soft $J\mathrm{/}\mathrm{\Psi }$ production in B decays, we investigate $B^0\to J\mathrm{/}\mathrm{\Psi }{D}^{(\star )}$ and ${\eta }_c{D}^{(\star )}$ decays in perturbative QCD. We find that, within that framework, these decays are calculable since the heavy $c\bar{c}$ pair in the final states is created by a hard gluon. The branching ratios are estimated to be around $10^{-7}\sim 10^{-8}$, too small to be consistent with the data, suggesting that other mechanism(s) contribute to the observed excess of soft $J\mathrm{/}\mathrm{\Psi }$ in ${B}^0 \to J/\Psi + X$decays\mathrm{.}Thepossibilityoftheproductionofahybrid$s{\bar d}g$ meson with mass about 2 GeV is briefly entertained.