Measurement of the Λ_b⁰ Lifetime in the Decay Λ_b⁰ → J/ψΛ⁰ with the D0 Detector

Authors

V. M. Abazov, Joint Institute for Nuclear Research, Dubna, Russia
Gregory Snow, University of Nebraska-LincolnFollow
D0 Collaboration

Date of this Version

3-18-2005

Comments

Published by American Physical Society. Phys. Rev. Lett. 94, 102001 (2005). http://prl.aps.org. Copyright © 2005 American Physical Society. Used by permission.

Abstract

We present measurements of the Λ_b⁰ lifetime in the exclusive decay channel Λ_b⁰ → J/ψΛ⁰, with J/ψ → μ⁺μ^- and Λ⁰ → pπ^-, the B⁰ lifetime in the decay Λ⁰ → J/ψK_s⁰ with J/ψ → μ⁺μ^- and K_s⁰ → π⁺π^-, and the ratio of these lifetimes. The analysis is based on approximately 250 pb^-1 of data recorded with the D0 detector in pp̅ collisions at √s = 1.96 TeV. The Λ_b⁰ lifetime is determined to be τ(Λ_b⁰) = 1.22_-0.18^+0.22(stat) ± 0.04(syst) ps, the B⁰ lifetime τ(B⁰) = 1.40_-0.10^+0.11(stat) ± 0.03(syst) ps, and the ratio τ(Λ_b⁰)/τ(B⁰) = 0.87_-0.14^+0.17 (stat) ± 0.03(syst). In contrast with previous measurements using semileptonic decays, this is the first determination of the Λ_b⁰ lifetime based on a fully reconstructed decay channel.