Abstract
Abstract We derive constraints on Wilson coefficients of dimension-six effective operators probing the b → s transition, using recent improved measurements of the rare decays B s → μ + μ −, B → Kμ + μ − and B → K * μ + μ − and including all relevant observables in inclusive and exclusive decays. We consider operators present in the SM as well as their chirality-flipped counterparts and scalar operators. We find good agreement with the SM expectations. Compared to the situation before winter 2012, we find significantly more stringent constraints on the chirality-flipped coefficients due to complementary constraints from B → Kμ + μ − and B → K * μ + μ − and due to the LHCb measurement of the angular observable S 3 in the latter decay. We also list the full set of observables sensitive to new physics in the low recoil region of B → K * μ + μ −.
Highlights
We include the decays B → Kμ+μ− and Bs → μ+μ− in the determination of Wilson coefficients constraints
At the 95% C.L., the Wilson coefficients are still compatible with their SM values
The branching ratio of B → Kμ+μ− constitutes a important constraint on the chirality-flipped Wilson coefficients C9,10, for which it is complementary to B → K∗μ+μ−
Summary
Define all the Wilson coefficients at a matching scale of 160 GeV. In the SM, the primed coefficients as well as CS,P are negligibly small. We use an updated value for the neutral B meson decay constant fB = 190(4) MeV [34] relevant for the normalization of B → K∗ form factors, the effect being an increased SM prediction for the branching ratio in the low q2 bin (but small with respect to the theory uncertainty);. For the extrapolation of form factors to high q2, where we use the results of [40], we take into account the error correlations between the fitted expansion parameters This leads to a very small increase in the estimated theory uncertainties. Since the B → K transition does not receive contributions from an axial vector current, the primed Wilson coefficients enter the B → Kμ+μ− observables always in conjunction with their unprimed counterparts as (Ci + Ci) This is complementary to the B → K∗μ+μ− decay and is useful to constrain the chirality-flipped operators. We obtain the SM prediction quoted in table 1
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