Searches for $\Lambda_{b}^{0}$ and $\Xi_{b}^{0}$ decays to $K_{\mathrm S}^{0}p\pi^{-}$ and $K_{\mathrm S}^{0}pK^{-}$ final states with the first observation of the $\Lambda_{b}^{0} \to K_{S}^{0}p\pi^{-}$ decay

TL;DR

This paper reports the first observation of the decay $\Lambda_b^0 o K_S^0 p \pi^-$, measures its CP asymmetry, and searches for related decays, setting upper limits where no signals are observed, based on 1.0 fb$^{-1}$ of data.

Contribution

The paper presents the first observation of the $\Lambda_b^0 o K_S^0 p \pi^-$ decay and provides measurements of its CP asymmetry, along with searches for other beauty baryon decays.

Findings

First observation of $\Lambda_b^0 o K_S^0 p \pi^-$ decay with 8.6$\sigma$ significance.

CP asymmetry measurement is consistent with zero.

Upper limits set for other unobserved decay modes.

Abstract

A search for previously unobserved decays of beauty baryons to the final states $K^0_{\mathrm{S}}p\pi^-$ and $K^0_{\mathrm{S}}pK^-$ 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 $\Lambda^0_b \rightarrow K^0_{\mathrm{S}}p\pi^-$ 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 $\Lambda^0_b \rightarrow K^0_{\mathrm{S}}pK^-$ decays, $\Xi^0_b$ decays to both $K^0_{\mathrm{S}}p\pi^-$ and $K^0_{\mathrm{S}}pK^-$ final states, and the $\Lambda^0_b \rightarrow D^-_s (K^0_{\mathrm{S}}K^-)p$ decay, and upper limits on their branching fractions are reported.