Depending on the assumptions on the power corrections to the exclusive b -> s l+ l- decays, the latest data of the LHCb collaboration - based on the 3 fb^-1 data set and on two different experimental analysis methods - still shows some tensions with the SM predictions. We present a detailed analysis of the theoretical inputs and various global fits to all the available b -> s l+ l- data. This constitutes the first global analysis of the new data of the LHCb collaboration based on the hypothesis that these tensions can be at least partially explained by new physics contributions. In our model-independent analysis we present one-, two-, four-, and also five-dimensional global fits in the space of Wilson coefficients to all available b -> s l+ l- data. We also compare the two different experimental LHCb analyses of the angular observables in B -> K* mu+ mu-. We explicitly analyse the dependence of our results on the assumptions about power corrections, but also on the errors present in the form factor calculations. Moreover, based on our new global fits we present predictions for ratios of observables which may show a sign of lepton non-universality. Their measurements would crosscheck the LHCb result on the ratio R_K = BR(B+ -> K+ mu+ mu-) / BR(B+ -> K+ e+ e-) in the low-q^2 region which deviates from the SM prediction by 2.6 sigma.Comment: 41 pages, 24 figures. v2: references and comment on 1006.4945 [hep-ph] adde
We present a brief update of our model-independent analyses of the b → s data presented in the articles published in Phys. Rev. D96 (2017) 095034 and Phys. Rev. D98 (2018) 095027 based on new data on R K by LHCb, on R K * by Belle, and on B s,d → µ + µ − by ATLAS. * This is an addendum to Ref. [1], "Lepton Nonuniversality in Exclusive b → s + − Decays", and Ref. [2], "Hadronic and New Physics Contributions to b → s Transitions".
There are some slight tensions with the SM predictions within the latest LHCb measurements. Besides the known anomaly in one angular observable of the rare decay B → K * µ + µ − , another small discrepancy recently occurred. The ratio R K = BR(B + → K + µ + µ − )/BR(B + → K + e + e − ) in the low-q 2 region has been measured by LHCb showing a 2.6σ deviation from the SM prediction. In contrast to the anomaly in the rare decay B → K * µ + µ − which is affected by power corrections, the ratio R K is theoretically rather clean. We analyse all the b → s data with global fits and in particular explore the possibility of breaking of lepton universality. Possible cross-checks with an analysis of the inclusive B → X s + − decay are also explored.
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 à offer some new insight beyond the previous measurement of R K. We work out the present significance for nonuniversality, and argue that claims of 5σ deviations from the standard model based on all present b → sl þ l − data including the ratios are misleading and are at present still based on guesstimates of hadronic power corrections in the b → sl þ l − angular observables. We demonstrate that only a small part of the luminosity of 50 fb −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 ðÃÞ 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.
Assuming the source of the anomalies observed recently in b → s data to be new physics, there is a priori no reason to believe that -in the effective field theory language -only one type of operator is responsible for the tensions. We thus perform for the first time a global fit where all the Wilson coefficients which can effectively receive new physics contributions are considered, allowing for lepton flavour universality breaking effects as well as contributions from chirality flipped and scalar and pseudoscalar operators, and find the SM pull taking into account all effective parameters. As a result of the full fit to all available b → s data including all relevant Wilson coefficients, we obtain a total pull of 4.1σ with the SM hypothesis assuming 10% error for the power corrections. Moreover, we make a statistical comparison to find whether the most favoured explanation of the anomalies is new physics or underestimated hadronic effects using the most general parameterisation which is fully consistent with the analyticity structure of the amplitudes. This Wilks' test will be a very useful tool to analyse the forthcoming B → K * µ + µ − data. Because the significance of the observed tensions in the angular observables in B → K * µ + µ − is presently dependent on the theory estimation of the hadronic contributions to these decays, we briefly discuss the various available approaches for taking into account the long-distance hadronic effects and examine how the different estimations of these contributions result in distinct significance of the new physics interpretation of the observed anomalies.
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