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

**Authors:** Marcel Alguer\'o, Bernat Capdevila, Andreas Crivellin, S\'ebastien, Descotes-Genon, Pere Masjuan, Joaquim Matias, Mart\'in Novoa-Brunet, Javier, Virto

arXiv: 1903.09578 · 2020-06-17

## TL;DR

This paper conducts a comprehensive, model-independent analysis of $b	o s\,\ell^+\ell^-$ decays, revealing new patterns of New Physics, especially involving lepton-flavour universality violation and right-handed couplings, with implications for related anomalies.

## Contribution

It identifies new NP scenarios with LFU and LFUV contributions, incorporating recent experimental data, and proposes four novel models consistent with observations.

## Key findings

- Evidence for right-handed couplings in Wilson coefficients.
- LFUV left-handed lepton coupling improves data fit.
- LFU NP scenario links to $b\to c\tau\nu$ anomalies with 7$\sigma$ significance.

## Abstract

We perform a model-independent global fit to $b\to s\ell^+\ell^-$ 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 $R_K$ and $R_{K^*}$, respectively. Our analysis, updating Refs. [1,2] and including these new data, suggests the presence of right-handed couplings encoded in the Wilson coefficients ${\cal C}_{9'\mu}$ and ${\cal C}_{10'\mu}$. It also strengthens our earlier observation that a lepton flavour universality violating (LFUV) left-handed lepton coupling (${\cal C}_{9\mu}^{\rm V}=-{\cal C}_{10\mu}^{\rm V}$), often preferred from the model building point of view, accommodates the data better if lepton-flavour universal (LFU) NP is allowed, in particular in ${\cal C}_{9}^{\rm U}$. Furthermore, this scenario with LFU NP provides a simple and model-independent connection to the $b\to c\tau \nu$ anomalies, showing a preference of $\approx 7\,\sigma$ with respect to the SM. It may also explain why fits to the whole set of $b\to s\ell^+\ell^-$ data or to the subset of LFUV data exhibit stronger preferences for different NP scenarios. Finally, motivated by $Z^\prime$ 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 $B\to K^*\mu\mu$ angular distribution released in 2020 by the LHCb collaboration.

## Full text

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## Figures

46 figures with captions in the complete paper: https://tomesphere.com/paper/1903.09578/full.md

## References

47 references — full list in the complete paper: https://tomesphere.com/paper/1903.09578/full.md

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Source: https://tomesphere.com/paper/1903.09578