Looking for a hidden-charm pentaquark state with strangeness $S=-1$ from ${\mathrm{\Xi }}_b^{-}$ decay into $J\mathrm{/}\psi K^{-}\mathrm{\Lambda }$

Assuming that the recently observed hidden-charm pentaquark state, $P_c(4450)$, is of molecular nature as predicted in the unitary approach, we propose to study the decay of ${\mathrm{\Xi }}_b^{-}\to J\mathrm{/}\psi K^{-}\mathrm{\Lambda }$ to search for the strangeness counterpart of the $P_c(4450)$. There are three ingredients in the decay mechanism: the weak decay mechanism, the hadronization mechanism, and the finite state interactions in the meson-baryon system of strangeness $S=-2$ and isospin $I=1\mathrm{/}2$ and of the $J\mathrm{/}\psi \mathrm{\Lambda }$. All these have been tested extensively. As a result, we provide a genuine prediction of the differential cross section where a strangeness hidden-charm pentaquark state, the counterpart of the $P_c(4450)$, can be clearly seen. The decay rate is estimated to be of similar magnitude as the $\Lambda_b^0\rightarrow J/\psi K^- p$ observed by the LHCb collaboration.