Observation of new baryons in the $\Xi_b^-\pi^+\pi^-$ and $\Xi_b^0\pi^+\pi^-$ systems

TL;DR

This paper reports the first observation of two new baryonic states in specific decay channels and confirms a previously observed state, improving measurements of known baryons using LHCb data.

Contribution

It introduces the discovery of two new baryons, confirms a known state, and measures properties of existing baryons with improved precision.

Findings

Discovery of two new baryons in $\Xi_b^0\pi^+\pi^-$ and $\Xi_b^-\pi^+\pi^-$ channels.

Confirmation of the $\Xi_b(6100)^-\) state.

Observation of a new decay mode of the $\Xi_b^0\) baryon.

Abstract

The first observation and study of two new baryonic structures in the final state $\Xi_b^0\pi^+\pi^-$ and the confirmation of the $\Xi_b(6100)^-$ state in the $\Xi_b^-\pi^+\pi^-$ decay mode are reported using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9$\mathrm{fb}^{-1}$. In addition, the properties of the known $\Xi_b^{*0}$, $\Xi_b^{'-}$ and $\Xi_b^{*-}$ resonances are measured with improved precision. The new decay mode of the $\Xi_b^0$ baryon to the $\Xi_c^+\pi^-\pi^+\pi^-$ final state is observed and exploited for the first time in these measurements.