Bottom Baryon Decays to Pseudoscalar Meson and Pentaquark

Based on SU(3) flavor symmetry, we decompose the decay amplitudes of bottom baryon decays to a pseudoscalar meson and an octet (a decuplet) pentaquark in terms of three (two) invariant amplitudes $T_1$ and $T_{2,3}$ (${\tilde{T}}_1$ and ${\tilde{T}}_2$) corresponding to external $W$-emission and internal $W$-emission diagrams, respectively. For antitriplet bottom baryons ${\mathrm{\Lambda }}_b^0,{\mathrm{\Xi }}_b^0$ and ${\mathrm{\Xi }}_b^{-}$, their decays to a decuplet pentaquark proceed only through the internal $W$-emission diagram. Assuming the dominance from the external $W$-emission amplitudes, we present an estimate of the decay rates relative to ${\mathrm{\Lambda }}_b^0\to P_p^{+}{K}^{-}$, where $P_p^{+}$ is the hidden-charm pentaquark with the same light quark content as the proton. Hence, our numerical results will provide a very useful guideline to the experimental search for pentaquarks in bottom baryon decays. For example, ${\mathrm{\Xi }}_b^0\to P_{{\mathrm{\Sigma }}^{+}}{K}^{-}$, $\Xi_b^-\to P_{\Sigma^-}\bar K^0$,$\Omega_b^-\to P_{\Xi^-}\bar K^0$and$\Omega_b^-\to P_{\Xi^0}K^-$mayhaveratescomparabletothatof$\Lambda_b^0\to P_p^+K^-$ and these modes should be given the higher priority in the experimental searches for pentaquarks.