Measurement of the $\Xi_b^-$ and $\Omega_b^-$ baryon lifetimes
  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. 
LHCb collaboration: R. Aaij, B. Adeva, M. Adinolfi, A. Affolder, Z.   Ajaltouni, J. Albrecht, F. Alessio, M. Alexander, S. A...
hep-ex