6533b82efe1ef96bd1292695

RESEARCH PRODUCT

Lepton nonuniversality in exclusive b→sℓℓ decays

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The LHCb measurements of certain ratios of decay modes testing lepton flavor nonuniversality might open an exciting world of new physics beyond the standard model. The latest LHCb measurements of ${R}_{{K}^{*}}$ offer some new insight beyond the previous measurement of ${R}_{K}$. We work out the present significance for nonuniversality, and argue that claims of $5\ensuremath{\sigma}$ deviations from the standard model based on all present $b\ensuremath{\rightarrow}s{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ data including the ratios are misleading and are at present still based on guesstimates of hadronic power corrections in the $b\ensuremath{\rightarrow}s{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ angular observables. We demonstrate that only a small part of the luminosity of $50\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ foreseen to be accumulated by the LHCb will be needed to offer soon a definite answer to the present question of whether we see a very small glimpse of lepton flavor nonuniversal new physics or not. We also present new predictions for other ratios based on our analysis of the present measurements of the ratios ${R}_{{K}^{(*)}}$ and analyze if they are able to differentiate between various new physics options within the effective field theory at present or in the near future.