Aula Conversi (Dipartimento di Fisica - Ed. G. Marconi)
Aula Conversi
Dipartimento di Fisica - Ed. G. Marconi
Description
The rare decay B->K^* l l provides diverse ways of probing new physics through its complex angular distribution, while benefitting from a relatively good theoretical control. In particular, there has been significant recent activity based on an apparent anomaly in the LHCb measurements of the angular distribution term I_5 (or P'_5). I will advocate a systematic helicity-based description with makes the BSM sensitivity and the theory errors more transparent. I will demonstrate that the suppression of certain helicity amplitudes holds in the SM even after including the hadronic weak Hamiltonian (charm loops etc), providing in particular clean probes of right-handed b->s currents. I will also show that modest levels of power corrections to the heavy-quark-limit relations between form factors may allow to accommodate the current LHCb anomaly in the SM.
