Measurement of branching fractions and rate asymmetries in the rare decays B → K(*)ℓ+ℓ−

Abstract

In a sample of 471 × 10 6 B ¯¯¯ B events collected with the BABAR detector at the PEP-II e + e − collider we study the rare decays B → K ( * ) ℓ + ℓ − , where ℓ + ℓ − is either e + e − or μ + μ − . We report results on partial branching fractions and isospin asymmetries in seven bins of dilepton mass-squared. We further present C P and lepton-flavor asymmetries for dilepton masses below and above the J / ψ resonance. We find no evidence for C P or lepton-flavor violation. The partial branching fractions and isospin asymmetries are consistent with the Standard Model predictions and with results from other experiments.