Measurement of the $\bar{B}_s^0$ Meson
Lifetime Using Semileptonic Decays
with Single Lepton Datasets in CDF Run II




Text for the blessed web page - CDF note 7757

The CDF Collaboration

13 August 2005

Abstract:

The lifetime of the $\bar{B}_s^0$ meson is measured in CDF Run II using the partially reconstructed semileptonic decay $\bar{B}_s^0 \rightarrow \ell^- \bar{\nu}D_s^+ X$, where $\ell^-$ is a lepton ($e^-$ or $\mu^-$) and the $D_s^+$ meson is reconstructed in the $\phi \pi ^+$ decay mode. The data come from 8 GeV single lepton trigger datasets, corresponding to an integrated luminosity of about 360 pb$^{-1}$. We find the $\bar{B}^0_s$ meson lifetime to be $c\tau(\bar{B}_s^0) = 414.0 \pm 16.6 \ ^{+15.6}_{-13.8}\ \mu$m, or $\tau(\bar{B}_s^0) = 1.381 \pm 0.055\ ^{+0.052}_{-0.046}$ ps, where the first uncertainties are statistical and the second are systematic. We also measure the ratio of the $\bar{B}_s^0$ and $\bar{B}^0$ meson lifetimes to be $\tau(\bar{B}_s^0)/\tau(\bar{B}^0) = 0.938 \pm 0.044 \ ^{+0.049}_{-0.046}$, where $\tau(\bar{B}^0)$ is taken from the previous $B^-/\bar{B}^0$ lifetime analysis using the semileptonic decays.