Hidden charm ${\mathcal{P}}_{cs}(4338{)}^0$ production in baryonic $B^{-}\to J\mathrm{/}\psi \mathrm{\Lambda }\bar{p}$ decay

We investigate the resonant baryonic $B$ decay $B^{-}\to {\mathcal{P}}_{cs}^0\bar{p},{\mathcal{P}}_{cs}^0\to J\mathrm{/}\psi \mathrm{\Lambda }$, where ${\mathcal{P}}_{cs}^0\equiv {\mathcal{P}}_{cs}(4338{)}^0$ is identified as a hidden charm pentaquark candidate with strangeness. By interpreting ${\mathcal{P}}_{cs}^0$ as the ${\mathrm{\Xi }}_c\bar{D}$ molecule that strongly decays into $J\mathrm{/}\psi \mathrm{\Lambda }$ and ${\eta }_c\mathrm{\Lambda }$, we discover a dominant triangle rescattering effect for $B^{-}\to {\mathcal{P}}_{cs}^0\bar{p}$, initiated by $B^{-}\to J\mathrm{/}\psi K^{-}$. Through the exchange of a $\bar{\mathrm{\Lambda }}$ anti-baryon, $J\mathrm{/}\psi$ and $K^{-}$ undergo rescattering, transforming into ${\mathcal{P}}_{cs}^0$ and $\bar{p}$, respectively. Based on this rescattering mechanism, we calculate $\mathcal{B}(B^{-}\to {\mathcal{P}}_{cs}^0\bar{p},{\mathcal{P}}_{cs}^0\to J\mathrm{/}\psi \mathrm{\Lambda })=(1.4_{-1.1}^{+2.1})\times {10}^{-6}$, which is consistent with the measured data.