2018 Impact factor 4.843
Particles and Fields
Eur. Phys. J. C 2, 407-416
DOI 10.1007/s100529800839

A measurement of the $\bf \mathrm{B_s^0}$ lifetime using reconstructed $\bf \mathrm{ D_s^-}$ mesons

The OPAL Collaboration, K.Ackerstaff8 et al.

8 CERN, European Organisation for Particle Physics, CH-1211 Geneva 23, Switzerland

Received: 25 July 1997 / Published online: 10 March 1998

Abstract
We report a measurement of the $\mathrm{B_s^0}$meson lifetime from $\mathrm{B_s^0}\to \mathrm{ D_s^-}\rm{X}$ decays, where $\mathrm{ D_s^-}$ mesons are reconstructed in the $\mathrm{ D_s^-}\to
\mathrm{\phi\pi^-}$ and $\mathrm{ D_s^-}\to\mathrm{K^{*0}K^-}$ decay channels. From approximately 3.7 million hadronic $\mathrm{Z}^0$ decays recorded by the OPAL detector at LEP a sample is selected containing 911 $\pm$ 83 candidates, of which $519 \pm 136$ are estimated to be from $\mathrm{B_s^0}$ meson decays. Fitting the distribution of the distance from the beam spot to the decay vertex of the $\mathrm{ D_s^-}$ candidates with an unbinned likelihood function we measure

\begin{displaymath}
\mbox{$\mathrm{\tau(B_s^0)}$}= \mbox{$1.72 ^{+0.20}_{-0.19}$}\mbox{$^{+0.18}_{-0.17}$}\mbox{$\mathrm{\,ps}$},\end{displaymath}

where the errors are statistical and systematic, respectively.


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