Effective lagrangian for heavy and light mesons. Radiative B decays

Abstract

We make use of the information obtained from semileptonic decays of B and D mesons, within an effective lagrangian description based on heavy quark theory and on chiral expansion, to study the radiative decays B → K ∗γ and B s → øγ , and the pair conversion processes B → Ke + e − and B → K ∗e +e − . We discuss with care the required extrapolations from zero recoils. We obtain a BR(B → K ∗γ) between 1.3× 10 − and 4.1 × 10 −5 and BR ( B s → φγ) between 1.4 × 10 −5 and 4.5 × 10 −5, with errors mainly arising from the present uncertainty in the K the pair conversion process we study in particular the lepton effective mass distributions whose measurements would allow for an understanding of both long distance and short distance contributions to such processes.