Phase-space anisotropy signatures as a probe of New Physics in b→sμ⁺μ⁻ decays

Rare semileptonic b→sμ⁺μ⁻ transitions are among the most interesting channels in indirect searches for New Physics (NP) effects. Recent studies of these processes indicate a suppression in decay rates and deviations in phase-space distributions of decay products with respect to Standard Model (SM) predictions. Since the confirmation of these anomalies are currently limited by large theoretical uncertainties, complementary experimental avenues are essential to probe these phenomena. An interesting possible feature in the case of NP is the introduction of new weak phase(s) beyond the SM one, which in turn can interfere with SM processes and manifest as distinct asymmetries in the phase space of the decay. Multibody decays have enhanced sensitivity to the phenomenon when several different intermediate quantum amplitudes can interfere, resulting in distinctive patterns of excess or deficit in regions of the phase space. In this work, we propose a novel set of observables that are sensitive to local asymmetry signatures in the phase space of non-exclusive multibody rare semileptonic decays, and are not hindered by the sizable SM uncertainties. In this talk I will discuss the possible magnitude of these effects and the perspectives to observe this phenomenon at collider experiments.