Abstract
Assuming the source of the anomalies observed recently in $b \to s$ 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 $b \to s$ data including all relevant Wilson coefficients, we obtain a total pull of 4.1$\sigma$ 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 $B\to K^* \mu^+ \mu^-$ data. Because the significance of the observed tensions in the angular observables in $B \to K^* \mu^+\mu^-$ 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.
Highlights
Among the most significant particle physics measurements hinting to the observation of new physics (NP) are the tensions between the standard model (SM) predictions and the corresponding experimental measurements in several b → slþl− decays
We examine how the significance of the preferred new physics scenarios changes depending on the employed method for estimating the power corrections
The calculations are performed at q2 < 0 where the theory predictions for the leading terms in QCD factorization (QCDf) [42,43,50,69] as well as the subleading terms in light-cone sum rule (LCSR) [31,32] are reliable and in combination with the experimental information on the B → J=ψKÃ and B → ψð2SÞKÃ decays, the hadronic contributions due to the charm loops are estimated in the physical region up to the ψð2SÞ resonance
Summary
Among the most significant particle physics measurements hinting to the observation of new physics (NP) are the tensions between the standard model (SM) predictions and the corresponding experimental measurements in several b → slþl− decays. While an appropriate choice could offer specific form factor independent observables (at leading order), when considering the full set of angular observables and taking into account the correlations (both experimental and theoretical) in the global fit, the uncertainty merely shifts from one observable to another and a change of basis would not offer further physical information [35]. Another source of hadronic uncertainties is due to nonlocal contributions from four-quark operators, especially from charm loops, which give rise to the nonfactorizable power corrections. It is due to the similar effect from the short-distance C9 (and C7) of Hselff and the long-distance contribution from Hhefafd that there is an ambiguity in separating NP effects of the type CN9 P (and CN7 P) from nonfactorizable hadronic contributions
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