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

2019; Springer Science+Business Media; Volume: 79; Issue: 8 Linguagem: Inglês

10.1140/epjc/s10052-019-7216-3

1434-6052

Marcel Algueró, Bernat Capdevila, Andreas Crivellin, Sébastien Descotes–Genon, Pere Masjuan, Joaquim Matias, Javier Virto,

Computational Physics and Python Applications

We perform a model-independent global fit to $$b\rightarrow s\ell ^+\ell ^-$$ 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. Capdevila et al. (J Virto JHEP 1801:093, 2018) and Algueró et al. (J Matias Phys Rev D 99(7):075017, 2019) and including these new data, suggests the presence of right-handed couplings encoded in the Wilson coefficients $${{{\mathcal {C}}}}_{9'\mu }$$ and $${{{\mathcal {C}}}}_{10'\mu }$$. It also strengthens our earlier observation that a lepton flavour universality violating (LFUV) left-handed lepton coupling ($${{{\mathcal {C}}}}_{9\mu }^{\mathrm{V}}=-\,{{{\mathcal {C}}}}_{10\mu }^{\mathrm{V}}$$), often preferred from the model building point of view, accommodates the data better if lepton-flavour universal (LFU) NP is allowed, in particular in $${{{\mathcal {C}}}}_{9}^{\mathrm{U}}$$. Furthermore, this scenario with LFU NP provides a simple and model-independent connection to the $$b\rightarrow c\tau \nu $$ anomalies, showing a preference of $$\approx 7\,\sigma $$ with respect to the SM. It may also explain why fits to the whole set of $$b\rightarrow s\ell ^+\ell ^-$$ 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.