Measurement of the ${\ensuremath{\Lambda}}_{b}^{0}$ Lifetime in ${\ensuremath{\Lambda}}_{b}^{0}\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{c}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ Decays in $p\overline{p}$ Collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$

Measurement of the $Λ_{b}^{0}$ Lifetime in $Λ_{b}^{0} \to Λ_{c}^{+} π^{-}$ Decays in $p \bar{p}$ Collisions at $\sqrt{s} = 1.96 TeV$

T. Aaltonen et al. (CDF Collaboration)

Phys. Rev. Lett. 104, 102002 – Published 11 March 2010

Abstract

We report a measurement of the lifetime of the $Λ_{b}^{0}$ baryon in decays to the $Λ_{c}^{+} π^{-}$ final state in a sample corresponding to $1.1 {fb}^{- 1}$ collected in $p \bar{p}$ collisions at $\sqrt{s} = 1.96 TeV$ by the CDF II detector at the Tevatron collider. Using a sample of about 3000 fully reconstructed $Λ_{b}^{0}$ events we measure $τ (Λ_{b}^{0}) = 1.401 \pm 0.046 (stat) \pm 0.035 (syst) ps$ (corresponding to $c τ (Λ_{b}^{0}) = 420.1 \pm 13.7 (stat) \pm 10.6 (syst) μ m$ , where $c$ is the speed of light). The ratio of this result and the world average $B^{0}$ lifetime yields $τ (Λ_{b}^{0}) / τ (B^{0}) = 0.918 \pm 0.038$ (stat) and (syst), in good agreement with recent theoretical predictions.