Measurement of the Bs Meson Lifetime

TL;DR

This paper reports a measurement of the $B_s$ meson lifetime using semileptonic decay data from proton-antiproton collisions at Fermilab, providing a key parameter for understanding heavy meson behavior.

Contribution

The study presents the first measurement of the $B_s$ meson lifetime using semileptonic decay channels with a specific data sample from the Tevatron collider.

Findings

$B_s$ lifetime measured as 1.42 ps with statistical and systematic uncertainties.

Observation of $76 imes ext{signal events}$ for $B_s$ decays.

Additional measurement of $B_s$ lifetime in exclusive $J/\psi \phi$ decay mode.

Abstract

The lifetime of the $B_s$ meson is measured using the semileptonic decay $B_s \to D_s^- \ell^+ \nu X$. The data sample consists of 19.3 pb$^{-1}$ of $p \bar{p}$ collisions at $\sqrt{s} = 1.8$ TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1993. There are $76 \pm 8$ $\ell^{+} D_s^{-}$ signal events where the $D_s$ is identified via the decay $D_s^{-} \to \phi \pi^{-}$,~$\phi \to K^+ K^-$. Using these events, the $B_s$ meson lifetime is determined to be $\tau_{s} = 1.42^{+ 0.27}_{- 0.23} {\rm (stat)} \pm 0.11 {\rm (syst)}$ ps. A measurement of the $B_s$ lifetime in a low statistics sample of exclusive $B_s \to J/\psi \phi$ decays is also presented in this paper.