## Abstract

We construct an expression for a general lepton flavour universality (LFU) ratio, R_{X}, in b→sℓ^{+}ℓ^{−} decays in terms of a series of hadronic quantities which can be treated as nuisance parameters. This expression allows to include any LFU ratio in global fits of b→sℓ^{+}ℓ^{−} short-distance parameters, even in the absence of a precise knowledge of the corresponding hadronic structure. The absence of sizeable LFU violation and the approximate left-handed structure of the Standard Model amplitude imply that only a very limited set of hadronic parameters hamper the sensitivity of R_{X} to a possible LFU violation of short-distance origin. A global b→sℓ^{+}ℓ^{−} combination is performed including the measurement of R_{pK} for the first time, resulting in a significance of new physics of 4.2σ. In light of this, we evaluate the impact on the global significance of new physics using a set of experimentally promising non-exclusive R_{X} measurements that LHCb can perform, and find that they can significantly increase the discovery potential of the experiment.

Original language | English (US) |
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Article number | 137151 |

Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |

Volume | 830 |

DOIs | |

State | Published - Jul 10 2022 |

Externally published | Yes |

## ASJC Scopus subject areas

- Nuclear and High Energy Physics

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