Study of η − η′ mixing from measurement of B(s)0 → J/ψη(′) decay rates

The LHCb Collaboration

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A study of B and Bs meson decays into J/ψ η and J/ψ η′ final states is performed using a data set of proton-proton collisions at centre-of-mass energies of 7 and 8 TeV, collected by the LCHb experiment and corresponding to 3.0 fb−1 of integrated luminosity. The decay B0 → J/ψ η′ is observed for the first time. The following ratios of branching fractions are measured: (Formula Presented) where the third uncertainty is related to the present knowledge of fs/fd, the ratio between the probabilities for a b quark to form a Bs or a B0 meson. The branching fraction ratios are used to determine the parameters of η − η′ meson mixing. In addition, the first evidence for the decay Bs → ψ(2S)η′ is reported, and the relative branching fraction is measured, (Formula Presented) where the third uncertainty is due to the limited knowledge of the branching fractions of J/ψ and ψ(2S) mesons.
Original languageEnglish
Number of pages24
JournalJournal of High Energy Physics
Issue number1
Publication statusPublished - 2015
Externally publishedYes


  • Spectroscopy
  • Hadron-Hadron Scattering
  • QCD
  • Branching fraction
  • B physics

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