English

Emerging patterns of New Physics with and without Lepton Flavour Universal contributions

High Energy Physics - Phenomenology 2020-06-17 v6

Abstract

We perform a model-independent global fit to bs+b\to s\ell^+\ell^- observables to confirm existing New Physics (NP) patterns (or scenarios) and to identify new ones emerging from the inclusion of the updated LHCb and Belle measurements of RKR_K and RKR_{K^*}, respectively. Our analysis, updating Refs. [1,2] and including these new data, suggests the presence of right-handed couplings encoded in the Wilson coefficients C9μ{\cal C}_{9'\mu} and C10μ{\cal C}_{10'\mu}. It also strengthens our earlier observation that a lepton flavour universality violating (LFUV) left-handed lepton coupling (C9μV=C10μV{\cal C}_{9\mu}^{\rm V}=-{\cal C}_{10\mu}^{\rm V}), often preferred from the model building point of view, accommodates the data better if lepton-flavour universal (LFU) NP is allowed, in particular in C9U{\cal C}_{9}^{\rm U}. Furthermore, this scenario with LFU NP provides a simple and model-independent connection to the bcτνb\to c\tau \nu anomalies, showing a preference of 7σ\approx 7\,\sigma with respect to the SM. It may also explain why fits to the whole set of bs+b\to s\ell^+\ell^- data or to the subset of LFUV data exhibit stronger preferences for different NP scenarios. Finally, motivated by ZZ^\prime models with vector-like quarks, we propose four new scenarios with LFU and LFUV NP contributions that give a very good fit to data. We provide also an addendum collecting our updated results after including the data for the BKμμB\to K^*\mu\mu angular distribution released in 2020 by the LHCb collaboration.

Keywords

Cite

@article{arxiv.1903.09578,
  title  = {Emerging patterns of New Physics with and without Lepton Flavour Universal contributions},
  author = {Marcel Algueró and Bernat Capdevila and Andreas Crivellin and Sébastien Descotes-Genon and Pere Masjuan and Joaquim Matias and Martín Novoa-Brunet and Javier Virto},
  journal= {arXiv preprint arXiv:1903.09578},
  year   = {2020}
}

Comments

18 pages, 36 figures. Includes Addendum in an appendix with updated fit results and discussion taking into account the LHCb results on $B\to K^{*}\mu\mu$ angular observables of March, 2020. Colours of plots uniformized all over the paper. Version published at EPJC

R2 v1 2026-06-23T08:16:30.003Z