Measurement of the Lambda_b Lifetime in Lambda_b --> J/psi Lambda0 in p-pbar Collisions at sqrt(s)=1.96 TeV

TL;DR

This paper presents a highly precise measurement of the Lambda_b baryon lifetime in proton-antiproton collisions at 1.96 TeV, using the CDF II detector, which significantly exceeds previous measurement accuracy.

Contribution

The study provides the most precise Lambda_b lifetime measurement to date, using fully reconstructed decay channels in proton-antiproton collisions at Fermilab.

Findings

Measured tau(Lambda_b) = 1.593 ps with uncertainties.

Result is 3.2 sigma higher than the world average.

First measurement with this level of precision.

Abstract

We report a measurement of the Lambda_b lifetime in the exclusive decay Lambda_b --> J/psi Lambda0 in p-pbar collisions at sqrt(s) = 1.96 TeV using an integrated luminosity of 1.0 fb^{-1} of data collected by the CDF II detector at the Fermilab Tevatron. Using fully reconstructed decays, we measure tau(Lambda_b) = 1.593 ^{+0.083}_{-0.078} (stat.) +- 0.033 (syst.) ps. This is the single most precise measurement of tau(Lambda_b) and is 3.2 sigma higher than the current world average.