Charmful baryonicBdecaysB0→Λcp¯andB¯→Λcp¯π(ρ)

We study the two-body and three-body charmful baryonic B decays $B^0\to {\Lambda }_c\overline{p}$ and $\overline{B}\to {\Lambda }_c\overline{p}\pi \left(\rho \right).\mathrm{}$ The factorizable W-exchange contribution to $B^0\to {\Lambda }_c\overline{p}$ is negligible. Applying the bag model to evaluate the baryon-to-baryon weak transition matrix element, we find $\mathcal{B}(B^0\to {\Lambda }_c\overline{p})\lesssim 1.1\times {10}^{-5}|g_{B^{0}p{\Sigma }_b^{+}}/6\mathrm{}{|}^2$ with $g_{B^{0}p{\Sigma }_b^{+}}$ being a strong coupling for the decay ${\Sigma }_b^{+}\to B^{0}p$ and hence the predicted branching ratio is well below the current experimental limit. The factorizable contributions to $B^{-}\to {\Lambda }_c\overline{p}{\pi }^{-}$ can account for the observed branching ratio of order $6\times {10}^{-4}.$ The branching ratio for $B^{-}\to {\Lambda }_c\overline{p}{\rho }^{-}$ is larger than that of $B^{-}\to {\Lambda }_c\overline{p}{\pi }^{-}$ by a factor of about 2.6. We explain why the three-body charmful baryonic B decay has a larger rate than the two-body one, contrary to the case of mesonic B decays.