Observation of the decay Λ0b→pK−μ+μ− and a search for CP violation

Abstract : A search for CP violation in the decay Λ0b→pK−μ+μ− is presented. This decay is mediated by flavour-changing neutral-current transitions in the Standard Model and is potentially sensitive to new sources of CP violation. The study is based on a data sample of proton-proton collisions recorded with the LHCb experiment, corresponding to an integrated luminosity of 3 fb−1. The Λ0b→pK−μ+μ− decay is observed for the first time, and two observables that are sensitive to different manifestations of CP violation are measured, ΔACP≡ACP(Λ0b→pK−μ+μ−)−ACP(Λ0b→pK−J/ψ) and aTˆ−oddCP, where the latter is based on asymmetries in the angle between the μ+μ− and pK− decay planes. These are measured to be ΔACP=(−3.5±5.0(stat)±0.2(syst))×10−2, aTˆ−oddCP=(1.2±5.0(stat)±0.7(syst))×10−2, and no evidence for CP violation is found.
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Contributor : Claudine Bombar <>
Submitted on : Thursday, March 2, 2017 - 9:44:28 AM
Last modification on : Thursday, January 11, 2018 - 6:13:33 AM

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  • HAL Id : in2p3-01480995, version 1
  • ARXIV : 1703.00256



R. Aaij, L. Beaucourt, M. Chefdeville, D. Decamp, N. Déléage, et al.. Observation of the decay Λ0b→pK−μ+μ− and a search for CP violation. 2017. ⟨in2p3-01480995⟩



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