Measurement of the $\Omega_c^0$ and $\Xi_c^0$ baryon lifetimes using hadronic $b$-baryon decays

TL;DR

This paper reports precise measurements of the lifetimes of the $\Omega_c^0$ and $\Xi_c^0$ baryons using LHCb data, employing specific decay channels and normalization techniques to improve accuracy.

Contribution

The study provides the first measurements of these baryon lifetimes using fully reconstructed decay chains in a large dataset, with improved precision over previous results.

Findings

Measured $ au_{\Omega_c^0}$ as 276.3 fs with uncertainties

Measured $ au_{\Xi_c^0}$ as 149.2 fs with uncertainties

Results are consistent with prior measurements

Abstract

The lifetimes of the $\Omega_c^0$ and $\Xi_c^0$ baryons are measured using a $pp$ collision dataset collected by the LHCb experiment, corresponding to an integrated luminosity of $9~\rm{fb^{-1}}$. The charm baryons are produced in the fully reconstructed decay chains $\Omega_b^- \rightarrow \Omega_c^0 (\rightarrow pK^-K^-\pi^+)~\pi^-$ and $\Xi_b^- \rightarrow \Xi_c^0 (\rightarrow pK^-K^-\pi^+)~\pi^-$. The measurement uses topologically and kinematically similar $B^- \rightarrow D^0(\rightarrow K^-K^+\pi^-\pi^+)~\pi^-$ decays for normalisation. The measured lifetimes are $\tau_{\Omega_c^0} = 276.3 \pm 19.4~\rm{(stat)} \pm 1.8~\rm{(syst)} \pm 0.7~(\tau_{D^0})~\rm{fs}$, $\tau_{\Xi_c^0} = 149.2 \pm ~\,2.5~\rm{(stat)} \pm 0.9~\rm{(syst)} \pm 0.4~(\tau_{D^0})~\rm{fs}$, where the first uncertainty is statistical, the second systematic and the third due to the uncertainty of the $D^0$ lifetime. These results are consistent with previous measurements performed by the LHCb experiment.