LAUSR

We introduce a novel approach to extract the decay-amplitudes in B → V(→ M 1 M 2)ℓ+ℓ- processes, where V represents a meson with either J = 0 (S-wave) or J = 1 (P-wave). This approach enables the decay-amplitudes across the dihadron and dilepton invariant-masses to be extracted from data in a model-independent and continuous way. To achieve this, the angular decay rate is expressed in a way that allows the application of the sPlot technique to likelihood fits of the decay angles. We illustrate the abilities of this method on simulated B 0 → K + π - μ + μ - data, containing both S- and P-wave contributions to the K + π - system. We provide the weight functions and show that they allow the extraction of the absolute value of the P-wave and S-wave transversity amplitudes as a function of the dihadron and dimuon invariant-masses in a continuous, unbiased, and statistically-powerful way, while only relying on the angular distribution. As a consequence, the extracted amplitude shapes are model-independent — up to the angular terms included in the fit — and can be directly compared to theoretical predictions. A measurement using this technique can improve the sensitivity to potential new physics effects in b → sℓ+ℓ- transitions, as well as the understanding of hadronic form factors, particularly in the S-wave system.