A precision measurement of the B(s) meson lifetime in proton-antiproton collisions at center of mass energy = 1.96 TeV using partially and fully reconstructed modes

We present a measurement of the Bs lifetime in fully and partially reconstructed Bs → Ds(&phis;pi)X decays in ∼1.3 fb -1 of pp¯ collisions at s = 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron. We measure ctau(Bs) = 455.0 +/- 12.2 (stat.) +/- 8.2 (syst.) mum. The ratio of this result and the world average B0 lifetime yields tau( Bs)/tau(B0) = 0.99 +/- 0.03, which is in agreement with recent theoretical predictions.