Measurement of the $\hat{I}{\text{c◯}}_c^0$ and $\hat{I}{ž}_c^0$ baryon lifetimes using hadronic $b$-baryon decays

Abstract

The lifetimes of the $\hat{I}{\text{c◯}}_c^0$ and $\hat{I}{ž}_c^0$ baryons are measured using a $pp$ collision dataset collected by the LHCb experiment, corresponding to an integrated luminosity of $9\mathrm{f}{\mathrm{b}}^{-1}$. The charm baryons are produced in the fully reconstructed decay chains $\hat{I}{\text{c◯}}_b^{-}\to \hat{I}{\text{c◯}}_c^0(\to p{K}^{-}{K}^{-}\ddot{I}{€}^{+})\ddot{I}{€}^{-}$ and $\hat{I}{ž}_b^{-}\to \hat{I}{ž}_c^0(\to p{K}^{-}{K}^{-}\ddot{I}{€}^{+})\ddot{I}{€}^{-}$. The measurement uses topologically and kinematically similar $B^{-}\to D^0(\to K^{-}{K}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^{+})\ddot{I}{€}^{-}$ decays for normalisation. The measured lifetimes are $\ddot{I}{„}_{\hat{I}{\text{c◯}}_c^0}=276.3\pm 19.4(\mathrm{stat})\pm 1.8(\mathrm{syst})\pm 0.7(\ddot{\mathrm{I}}{„}_{{\mathrm{D}}^0})\mathrm{fs}$, $\ddot{I}{„}_{\hat{I}{ž}_c^0}=149.2\pm 2.5(\mathrm{stat})\pm 0.9(\mathrm{syst})\pm 0.4(\ddot{\mathrm{I}}{„}_{{\mathrm{D}}^0})\mathrm{fs}$, 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.

All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://lbfence.cern.ch/alcm/public/analysis/full-details/3875/ (LHCb public pages)