Searches for ${\Lambda }_b^0$ and ${\Xi }_b^0$ decays to $K_{\mathrm{S}}^{0}p{\pi }^{-}$ and $K_{\mathrm{S}}^{0}p{K}^{-}$ final states with the first observation of the ${\Lambda }_b^0\to K_S^{0}p{\pi }^{-}$ decay

Abstract

A search for previously unobserved decays of beauty baryons to the final states $K_{\mathrm{S}}^{0}p{\pi }^{-}$ and $K_{\mathrm{S}}^{0}p{K}^{-}$ is reported. The analysis is based on a data sample corresponding to an integrated luminosity of $1.0{\mathrm{fb}}^{-1}$ of $pp$ collisions. The ${\Lambda }_b^0\to K_{\mathrm{S}}^{0}p{\pi }^{-}$ decay is observed for the first time with a significance of $8.6\sigma$, and a measurement is made of the $CP$ asymmetry, which is consistent with zero. No significant signals are seen for ${\Lambda }_b^0\to K_{\mathrm{S}}^{0}p{K}^{-}$ decays, ${\Xi }_b^0$ decays to both $K_{\mathrm{S}}^{0}p{\pi }^{-}$ and $K_{\mathrm{S}}^{0}p{K}^{-}$ final states, and the ${\Lambda }_b^0\to D_s^{-}(K_{\mathrm{S}}^0{K}^{-})p$ decay, and upper limits on their branching fractions are reported.

4 pages