Abstract:
For the rare B meson decays, Bd ! K l+l and Bs ! l+l , the long distance effects are studied. The form factors which give a description of meson transition amplitudes in the effective Hamiltonian approach, are investigated by means of Wards Identities. These form factors are then compared with the other approaches in the literature , like Light Cone Sum Rules (LCSR) approach and Lattice QCD (LQCD) approach. Moreover, the Bd ! K l+l and Bs ! l+l branching ratios are computed in the framework of Standard Model and are compared with the experimental results and the other approaches, LCSR and LQCD. The differential branching fractions are given as a function of the squared-momentum transferred.
