Precision Measurement of the Λ0b Baryon Lifetime

The ratio of the Λ 0 b baryon lifetime to that of the ¯¯¯ B 0 meson is measured using 1.0     fb − 1 of integrated luminosity in 7 TeV center-of-mass energy p p collisions at the LHC. The Λ 0 b baryon is observed for the first time in the decay mode Λ 0 b → J / ψ p K − , while the ¯¯¯ B 0 meson deca...

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Bibliographic Details
Published in:Physical review letters 2013-09
Main Authors: Calvo Gómez, Míriam, Camboni, Alessandro, Comerma Montells, Albert, Garrido Beltrán, Lluís, Graciani Díaz, Ricardo, Graugés Pous, Eugeni, Oyanguren Campos, Arantza de, Pérez-Calero Yzquierdo, Antonio, Picatoste Olloqui, Eduardo, Potterat, Cédric, Rives Molina, Vicente José, Ruiz, Hugo (Ruiz Pérez), Ruiz Valls, Pablo, Vilasis-Cardona, Xavier, LHCb Collaboration
Format: Article
Language:English
Subjects:
Experiments
Física de partícules
Particle physics
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Summary:The ratio of the Λ 0 b baryon lifetime to that of the ¯¯¯ B 0 meson is measured using 1.0     fb − 1 of integrated luminosity in 7 TeV center-of-mass energy p p collisions at the LHC. The Λ 0 b baryon is observed for the first time in the decay mode Λ 0 b → J / ψ p K − , while the ¯¯¯ B 0 meson decay used is the well known ¯¯¯ B 0 → J / ψ π + K − mode, where the π + K − mass is consistent with that of the ¯¯¯¯ K * 0 ( 892 ) meson. The ratio of lifetimes is measured to be 0.976 ± 0.012 ± 0.006 , in agreement with theoretical expectations based on the heavy quark expansion. Using previous determinations of the ¯¯¯ B 0 meson lifetime, the Λ 0 b lifetime is found to be 1.482 ± 0.018 ± 0.012     ps . In both cases, the first uncertainty is statistical and the second systematic.
ISSN:0031-9007