Study of $\bar{B}\to \mathrm{\Lambda }\bar{p}\rho (\varphi )$ and $\bar{B}\to \mathrm{\Lambda }\bar{\mathrm{\Lambda }}{\bar{K}}^{\ast }$

We examine the three-body baryonic $\bar{B}\to \mathbf{B}{\bar{\mathbf{B}}}^{\mathbf{\prime }}V$ decays with $V$ vector mesons in the standard model. We can simultaneously explain the recent experimental data on the decays of $B^{-}\to \mathrm{\Lambda }\bar{p}{\rho }^0$ and $\bar{B}\to \mathrm{\Lambda }\bar{\mathrm{\Lambda }}{\bar{K}}^{\ast }$ based on the QCD counting rules and SU(3) flavor symmetry. We also predict that the decay branching ratios of $\bar B^0\to \Lambda\bar p ,\rho^+$and$B^-\to \Lambda\bar p ,\phi$are3.0and$1.5\times 10^{-6}$, respectively, which are promising to be observed by BELLE and BABAR at the $B$ factories.