Measurement of the $\Xi_b^-$ and $\Omega_b^-$ baryon lifetimes

TL;DR

This paper reports precise measurements of the lifetimes of the $\\Xi_b^-$ and $\\\Omega_b^-$ baryons using proton-proton collision data, confirming previous results and theoretical models.

Contribution

First precise lifetime measurements of the $\\\Xi_b^-$ and $\\\Omega_b^-$ baryons using a large data sample, improving accuracy over prior studies.

Findings

Measured $\\\Xi_b^-$ lifetime as 1.55 ps with uncertainties.

Measured $\\\Omega_b^-$ lifetime as 1.54 ps with uncertainties.

Results agree with previous experiments and theoretical predictions.

Abstract

Using a data sample of pp collisions corresponding to an integrated luminosity of $3~ \rm fb^{-1}$, the $\Xi_b^-$ and $\Omega_b^-$ baryons are reconstructed in the $\Xi_b^- \rightarrow J/\psi \Xi^-$ and $\Omega_b^- \rightarrow J/\psi \Omega^-$ decay modes and their lifetimes measured to be $\tau (\Xi_b^-) = 1.55\, ^{+0.10}_{-0.09}~{\rm(stat)} \pm 0.03\,{\rm(syst)}$ ps, $\tau (\Omega_b^-) = 1.54\, ^{+0.26}_{-0.21}~{\rm(stat)} \pm 0.05\,{\rm(syst)}$ ps. These are the most precise determinations to date. Both measurements are in good agreement with previous experimental results and with theoretical predictions.