Measurement of the Λb0 Lifetime in Λb0→Λc+π- Decays in pp Collisions at √s=1.96  TeV

We report a measurement of the lifetime of the Λb0 baryon in decays to the Λc+π- final state in a sample corresponding to 1.1fb-1 collected in pp̄ collisions at √s=1.96TeV by the CDF II detector at the Tevatron collider. Using a sample of about 3000 fully reconstructed Λb0 events we measure τ(Λb0)=1.401±0. 046(stat)±0.035(syst)ps (corresponding to cτ(Λb0)=420. 1±13.7(stat)±10.6(syst)μm, where c is the speed of light). The ratio of this result and the world average B0 lifetime yields τ(Λb0)/τ(B0)=0.918±0.038 (stat) and (syst), in good agreement with recent theoretical predictions. © 2010 The American Physical Society.