Measurement of b hadron lifetimes in exclusive decays containing a J/ψ in pp collisions at √s=1.96 TeV.

ABSTRACT

We report on a measurement of b-hadron lifetimes in the fully reconstructed decay modes B(+)→J/ψK(+), B°â†’J/ψK*(892)°, B°â†’J/ψK(s)°, and Λ(b)°â†’J/ψΛ° using data corresponding to an integrated luminosity of 4.3 fb⁻¹, collected by the CDF II detector at the Fermilab Tevatron. The measured lifetimes are τ(B(+))=[1.639±0.009(stat)±0.009(syst)] ps, τ(B°)=[1.507±0.010(stat)±0.008(syst)] ps, and τ(Λ(b)°)=[1.537±0.045(stat)±0.014(syst)] ps. The lifetime ratios are τ(B(+))/τ(B°)=[1.088±0.009(stat)±0.004(syst)] and τ(Λ(b)°)/τ(B°)=[1.020±0.030(stat)±0.008(syst)]. These are the most precise determinations of these quantities from a single experiment.