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arXiv · hep-ex/9802002

Measurements of the B^0_s and Λ_b Lifetimes

The OPAL Collaboration·K. Ackerstaff et al
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Abstract

This paper presents updated measurements of the lifetimes of the B^0_s meson and the Λ_b baryon using 4.4 million hadronic Z^0 decays recorded by the OPAL detector at LEP from 1990 to 1995. A sample of B^0_s decays is obtained using D_s^- \ell^+ combinations, where the D_s^- is fully reconstructed in the ϕπ^-, K^*0 K^- and K^- K^0_S decay channels and partially reconstructed in the ϕ\ell^- ν(bar) X decay mode. A sample of Λ_b decays is obtained using Λ_c^+ \ell^- combinations, where the Λ_c^+ is fully reconstructed in its decay to a p K^- π^+ final state and partially reconstructed in the Λ\ell^+ νX decay channel. From 172 +/- 28 D_s^- \ell^+ combinations attributed to B^0_s decays, the measured lifetime is τ(B^0_s) = 1.50 +0.16 -0.15 +/- 0.04 ps, where the errors are statistical and systematic, respectively. From the 129 +\- 25 \Lamda_c^+ \ell^- combinations attributed to Λ_b decays, the measured lifetime τ(Λ_b) = 1.29 +0.24 -0.22 +/- 0.06 ps, where the errors are statistical and systematic, respectively.

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The OPAL Collaboration, K. Ackerstaff et al. 1998-01-31. Measurements of the B^0_s and Λ_b Lifetimes. https://doi.org/10.1016/s0370-2693(98)00289-5

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