Measurement of the B 0 s Meson Lifetime Using Semileptonic Decays

The lifetime of the B0 s meson is measured using the semileptonic decay B0 s → D s l+νX. The data sample consists of about 110 pb−1 of pp̄ collisions at √ s = 1.8 TeV collected by the CDF detector at Fermilab. Four different D s decay modes are reconstructed resulting in approximately 600 D s l+ signal events. The B0 s meson lifetime is determined to be τ(B0 s ) = (1.36 ± 0.09 +0.06 −0.05) ps, where the first and second uncertainties are statistical and systematic, respectively. The B0 s meson decay length distribution is examined for a lifetime difference ∆Γ/Γ between the two mass eigenstates of the B0 s meson. An upper limit of ∆Γ/Γ < 0.83 is set at 95% confidence level. PACS numbers: 13.20 He, 13.25.Hw, 14.40.Nd Typeset using REVTEX