Measurement of the CKM angle γ and Bs0‐B̅s0 mixing frequency with Bs0→Dsh±π±π decays

LHCb Collaboration

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The CKM angle γ is measured for the first time from mixing-induced CP violation between Bs0→DsK±π±π and B̅s0→Ds±Kππ± decays reconstructed in proton-proton collision data corresponding to an integrated luminosity of 9 fb−1 recorded with the LHCb detector. A time-dependent amplitude analysis is performed to extract the CP-violating weak phase γ − 2βs and, subsequently, γ by taking the Bs0‐B̅s0 mixing phase βs as an external input. The measurement yields γ = (44 ± 12)° modulo 180°, where statistical and systematic uncertainties are combined. An alternative model-independent measurement, integrating over the five-dimensional phase space of the decay, yields γ=(44−13+20)° modulo 180°. Moreover, the Bs0‐B̅s0 oscillation frequency is measured from the flavour-specific control channel Bs0→Dsπ+π+π to be ∆ms = (17.757 ± 0.007(stat) ± 0.008(syst)) ps−1, consistent with and more precise than the current world-average value. 

Original languageEnglish
Article number137
Number of pages46
JournalJournal of High Energy Physics
Issue number3
Publication statusPublished - 15 Mar 2021

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).


  • B physics
  • CKM angle gamma
  • CP violation
  • Hadron-Hadron scattering (experiments)
  • Oscillation

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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