We report a measurement of the Lambda_b lifetime using a sample corresponding to 1.3 fb$^{ -1}$ of data collected by the D0 experiment in 2002--2006 during Run II of the Fermilab Tevatron collider. The Lambda_b baryon is reconstructed via the decay Lambda_b -> mu nu Lambda_c X. Using $4437 \pm 329$ signal candidates, we measure the Lambda_b lifetime to be $\tau(Lambda_b)$ = 1.290^{ +0.119}_{ -0.110}(stat) ^{ +0.087}_{ -0.091} (syst) ps, which is among the most precise measurements in semileptonic Lambda_b decays. This result is in good agreement with the world average value.
Categories: hep-ex