Estimates of B-decays into K-resonances and dileptons

Short and long distance contributions to the exclusive B-decays into various K-resonances and dileptons, i.e. B → Kⁱℓℓ̄(ℓ = e, μ, ν), are examined. The heavy quark effective theory has been used to calculate the hadronic matrix elements. Substantial branching fractions are obtained for the dileptonic B-decays into some higher excited states of K-mesons. The long distance (resonance) contributions to these exclusive rare B-decay modes dominate the short distance contributions mostly by two orders of magnitude. It is pointed out that, excluding the resonance contributions, the P-wave channels are dominant, accounting for about 50% of the inclusive B → X_sℓ⁺ℓ^- branching fraction.