Regular Article- Theoretical Physics Constraints on tensor and scalar couplings from B → K μ̄μ

e, μ, τ) depends on two parameters, the lepton forward– backward asymmetry, AFB, and the flat term, F H. Both are strongly suppressed in the standard model and constitute sen-sitive probes of tensor and scalar contributions. We use the latest experimental results for = μ in combination with the branching ratio of Bs → μ̄μ to derive the strongest model-independent bounds on tensor and scalar effective couplings to date. The measurement of FμH provides a complementary constraint to that of the branching ratio of Bs → μ̄μ and allows us – for the first time – to constrain all complex-valued (pseudo-)scalar couplings and their chirality-flipped counterparts in one fit. Based on Bayesian fits of various sce-narios, we find that our bounds even become tighter when vector couplings are allowed to deviate from the standard model and that specific combinations of angular observables in B → K ∗̄ are still allowed to be up to two orders of magnitude larger than in the standard model, which would place them in the region of LHCb’s sensitivity.