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

Abstract

We perform a model-independent global fit to b→ sℓ+ℓ- 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 RK and RK∗, 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 C9′μ and C10′μ. It also strengthens our earlier observation that a lepton flavour universality violating (LFUV) left-handed lepton coupling (C9μV=-C10μV), 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. Furthermore, this scenario with LFU NP provides a simple and model-independent connection to the b→ cτν anomalies, showing a preference of ≈7σ with respect to the SM. It may also explain why fits to the whole set of b→ sℓ+ℓ- data or to the subset of LFUV data exhibit stronger preferences for different NP scenarios. Finally, motivated by Z′ models with vector-like quarks, we propose four new scenarios with LFU and LFUV NP contributions that give a very good fit to data.