Measurement of lifetime and decay-width difference in B-S(0)-> J/psi phi decays

We measure the mean lifetime tau=2/(Gamma(L)+Gamma(H)) and the decay-width difference Delta Gamma=Gamma(L)-Gamma(H) of the light and heavy mass eigenstates of the B-s(0) meson, B-sL(0) and B-sH(0), in B-s(0)-> J/psi phi decays using 1.7 fb(-1) of data collected with the CDF II detector at the Fermilab Tevatron pp collider. Assuming CP conservation, a good approximation for the B-s(0) system in the standard model, we obtain Delta Gamma=0.076(-0.063)(+0.059)(stat)+/- 0.006(syst) ps(-1) and tau=1.52 +/- 0.04(stat)+/- 0.02(syst) ps, the most precise measurements to date. Our constraints on the weak phase and Delta Gamma are consistent with CP conservation.