# Precision measurement of the Lambda_b baryon lifetime

Abstract : The ratio of the \Lambda b baryon lifetime to that of the B0 meson is measured using 1.0/fb of integrated luminosity in 7 TeV center-of-mass energy pp collisions at the LHC. The \Lambda b baryon is observed for the first time in the decay mode \Lambda b -> J/\psi pK-, while the B0 meson decay used is the well known B0 -> J/\psi pi+K- mode, where the pi+ 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 B0 meson lifetime, the \Lambda 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.
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Submitted on : Monday, July 15, 2013 - 3:09:44 PM
Last modification on : Tuesday, January 25, 2022 - 12:48:09 PM

### Citation

R. Aaij, Y. Amhis, S. Barsuk, O. Callot, J. He, et al.. Precision measurement of the Lambda_b baryon lifetime. Physical Review Letters, American Physical Society, 2013, 111, pp.102003. ⟨10.1103/PhysRevLett.111.102003⟩. ⟨in2p3-00844572⟩

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