Speaker
Description
Deviations from the Standard Model have long been observed in semileptonic B-meson decays, notably b→ sll transitions, triggering speculations on potential New Physics effects in this sector. After the recent update of RK(*) and BR(B(s) → μμ) by the LHCb collaboration, the sole remaining significant deviations from the SM in FCNC B decays are found in the branching ratios of mesonic decays involving b → sμμ and in the angular observable P’5.
Unlike RK( ) and BR(B(s) → μμ), the observable BR(B(s) → Mμμ) (M = K(),φ,…) is theoretically challenging to predict accurately because of non-perturbative QCD contributions, both local and non-local. These contributions yield a theoretical error of order 30%, which can be as large as (sometimes larger than) the experimental uncertainty, and clearly hamper the potential of these observables for discovery.
At low hadronic recoil these form factors can be computed using lattice QCD methods, while the large recoil region requires analytical approaches such as Light Cone Sum Rules (LCSR). We undertake a new calculation of mesonic b → s form factors using LCSR with B-meson Distribution Amplitude. The form factors predictions are then used to compute relevant observables and perform fits of NP scenarios in the WET.
