An improved measurement of the BS0 lifetime

This letter presents an updated measurement of the lifetime of the Bs0 meson using 3.6 million hadronic Z0 decays recorded by the OPAL detector at LEP from 1990 to 1994. A sample of Bs0 decays is obtained using Ds−ℓ+ combinations, where the Ds− is reconstructed in either the φπ− or K∗0K− decay mode. From 79 ± 13 Dxℓ combinations attributed to Bs0 decays in this data sample, we measure τ(Bs0) = 1.54−0.21+0.25 ± 0.06 ps, where the errors are statistical and systematic, respectively.