Speaker
Description
To search for physics beyond the Standard Model (BSM) some of the most promising and sensitive observables are constituted by flavour-changing neutral-current $B$-meson decays mediated by $b \to s \ell\ell$ transitions. While several hints for deviations from the Standard Model have emerged over the recent years, it has also become clear that a more thorough theoretical understanding of non-local charm-loop effects, possibly mimicking BSM physics, is mandatory to turn these hints into robust results. To achieve this, experimental inputs can be combined with the fundamental principles of unitarity and analyticity via dispersive techniques to constrain the non-local hadronic form factors as tightly as possible. In our work we demonstrate that the expected analytic structures of these form factors, in particular including anomalous thresholds, can also be found in and matched onto perturbative partonic calculations. This further justifies the use of quark–hadron duality to provide additional theoretical constraints.