First Observation of the Decay Bs0K-μ+νμ and a Measurement of |Vub | / |Vcb |

LHCb Collaboration

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The first observation of the suppressed semileptonic Bs0 →K-μ+νμ decay is reported. Using a data sample recorded in pp collisions in 2012 with the LHCb detector, corresponding to an integrated luminosity of 2 fb-1, the branching fraction B(Bs0 →K-μ+νμ ) is measured to be [1.06±0.05(stat)±0.08(syst)]×10-4, where the first uncertainty is statistical and the second one represents the combined systematic uncertainties. The decay Bs0 →Ds-μ+νμ, where Ds- is reconstructed in the final state K+K-π-, is used as a normalization channel to minimize the experimental systematic uncertainty. Theoretical calculations on the form factors of the Bs0K- and Bs0Ds- transitions are employed to determine the ratio of the Cabibbo-Kobayashi-Maskawa matrix elements |Vub|/|Vcb| at low and high Bs0K- momentum transfer.

Original languageEnglish
Article number081804
JournalPhysical Review Letters
Issue number8
Publication statusPublished - 25 Feb 2021

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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