Measurement of the Λb lifetime and mass

UNSPECIFIED (2013) Measurement of the Λb lifetime and mass. Physical Review D – Particles and Fields, 87 (3): 032002. ISSN 1550-2368

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Abstract

A measurement of the Λb0 lifetime and mass in the decay channel Λb0→J/ψ(μ+μ-)Λ0(pπ-) is presented. The analysis uses a signal sample of about 2200 Λb0 and Λ̅ b0 decays that are reconstructed in 4.9  fb-1 of ATLAS pp collision data collected in 2011 at the LHC center-of-mass energy of 7 TeV. A simultaneous mass and decay time maximum likelihood fit is used to extract the Λb0 lifetime and mass. They are measured to be τΛb=1.449±0.036(stat)±0.017(syst)  ps and mΛb=5619.7±0.7(stat)±1.1(syst)  MeV.