Measurements of the B+, B0, B0s Meson and Λ0b Baryon Lifetimes

Measurements of b-hadron lifetimes are reported using pp collision data, corresponding to an integrated luminosity of 1.0 fb^−1, collected by the LHCb detector at a centre-of-mass energy of 7 TeV. Using the exclusive decays B+ → J/ψ K+, B0 → J/ψ K∗0(892), B0 → J/ψ K0s, Λ0b → J/ψ Λ and B0s → J/ψ ϕ the average decay times in these modes are measured to be τ_{B+ → J/ψ K+} = 1.637 ± 0.004 ± 0.003 ps, τ_{B0 → J/ψ K∗0} = 1.524 ± 0.006 ± 0.004 ps, τ_{B0 → J/ψ K0s} = 1.499 ± 0.013 ± 0.005 ps, τ_{Λ0b → J/ψ Λ} = 1.415 ± 0.027 ± 0.006 ps, τ_{B0s → J/ψ ϕ} = 1.480 ± 0.011 ± 0.005 ps, where the first uncertainty is statistical and the second is systematic. These represent the most precise lifetime measurements in these decay modes. In addition, ratios of these lifetimes, and the ratio of the decay-width difference, ΔΓ_d, to the average width, Γ_d , in the B0 system, ΔΓ_d/Γ_d = −0.044 ± 0.025 ± 0.011, are reported. All quantities are found to be consistent with Standard Model expectations.