Determination of short- and long-distance contributions in B° → K*° μ+ μ− decays

Abstract

[Abstract] An amplitude analysis of the B° → K*° μ+ μ− decay is presented. The analysis is based on data collected by the LHCb experiment from proton-proton collisions at √s =7, 8 and 13 TeV, corresponding to an integrated luminosity of 4.7 fb¯¹. For the first time, Wilson coefficients and nonlocal hadronic contributions are accessed directly from the unbinned data, where the latter are parametrized as a function of q² with a polynomial expansion. Wilson coefficients and nonlocal hadronic parameters are determined under two alternative hypotheses: the first relies on experimental information alone, while the second one includes information from theoretical predictions for the nonlocal contributions. Both models obtain similar results for the parameters of interest. The overall level of compatibility with the Standard Model is evaluated to be between 1.8 and 1.9 standard deviations when looking at the C9 Wilson coefficient alone, and between 1.3 and 1.4 standard deviations when considering the full set of C9,C10,C′9 and C′10 Wilson coefficients. The ranges reflect the theoretical assumptions made in the analysis.