Measurement of the Mass and Lifetime of the Ωb− Baryon

A proton-proton collision data sample, corresponding to an integrated luminosity of 3 fb^−1 collected by LHCb at √s = 7 and 8 TeV, is used to reconstruct 63 ± 9 Ωb− → Ωc0 π−, Ωc0 → p K− K− π+ decays. Using the Ξb− → Ξc0 π−, Ξc0 → p K− K− π+ decay mode for calibration, the lifetime ratio and the absolute lifetime of the Ωb− baryon are measured to be τ_{Ωb−}/τ_{Ξb−} = 1.11 ± 0.16 ± 0.03, τ_{Ωb−} = 1.78 ± 0.26 ± 0.05 ± 0.06 ps, where the uncertainties are statistical, systematic and from the calibration mode (for τ_{Ωb−} only). A measurement is also made of the mass difference, m_{Ωb−} − m_{Ξb−}, and the corresponding Ωb− mass, which yields m_{Ωb−} − m_{Ξb−} = 247.4 ± 3.2 ± 0.5 MeV/c2, m_{Ωb−} = 6045.1 ± 3.2 ± 0.5 ± 0.6 MeV/c2. These results are consistent with previous measurements.