### Abstract

Abstract: A study of B and B^{s} 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 B^{0} → 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 f_{s}/f_{d}, the ratio between the probabilities for a b quark to form a B^{s} or a B^{0} meson. The branching fraction ratios are used to determine the parameters of η − η^{′} meson mixing. In addition, the first evidence for the decay B^{s} → 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 language | English (US) |
---|---|

Article number | 24 |

Pages (from-to) | 1-24 |

Number of pages | 24 |

Journal | Journal of High Energy Physics |

Volume | 2015 |

Issue number | 1 |

DOIs | |

State | Published - 2015 |

### Keywords

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

### ASJC Scopus subject areas

- Nuclear and High Energy Physics

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## Cite this

^{′}mixing from measurement of B

_{(s)}

^{0}→ J/ψη

^{(′)}decay rates.

*Journal of High Energy Physics*,

*2015*(1), 1-24. [24]. https://doi.org/10.1007/JHEP01(2015)024