Forward-backward and isospin asymmetry for B → K *ℓ+ℓ- decay in the standard model and in supersymmetry

Abstract

We discuss two dedicated observables in exclusive B → K*ℓ+ℓ- decay that can be used to study effects of physics beyond the standard model, namely the forward-backward asymmetry in the lepton spectrum and the isospin-asymmetry between decays of charged and neutral B mesons. We consider the region of large recoil-energy (i.e. small invariant mass of the lepton pair), and employ the QCD factorization approach to exclusive B meson decays. Sub-leading effects in the heavy quark mass expansion are taken into account for the calculation of the isospin-asymmetry. We give predictions for decay asymmetries in the standard model, and its supersymmetric extension with minimal flavor violation, using parameter values allowed by current experimental constraints on B →X sγ decay. © SISSA/ISAS 2003.