Optimizing the basis of B → K * ℓ + ℓ - observables in the full kinematic range

Abstract

We discuss the observables for the B → K *(→ Kπ)ℓ + ℓ - decay, focusing on both CP-averaged and CP-violating observables at large and low hadronic recoil with special emphasis on their low sensitivity to form-factor uncertainties. We identify an optimal basis of observables that balances theoretical and experimental advantages, which will guide the New Physics searches in the short term. We discuss some advantages of the observables in the basis, and in particular their improved sensitivity to New Physics compared to other observables. We present predictions within the Standard Model for the observables of interest, integrated over the appropriate bins including lepton mass corrections. Finally, we present bounds on the S-wave contribution to the distribution coming from the B → K*0ℓ+ℓ- decay, which will help to establish the systematic error associated to this pollution. © 2013 SISSA.