摘要
Based on a data sample of 384 million BB pairs collected with the BABAR detector at the PEP-Ⅱ asymmetric e + e  ̄ storage ring,we measure branching fractions,direct CP,isospin and lepton-flavor asymmetries for the rare decays B → K (*) l + l ̄ in two di-lepton mass bins above and below the J/ψ resonance.For the B → K* l + l ̄ decay,we also measure the K* longitudinal polarization fraction and the di-lepton forwardbackward asymmetry.
Based on a data sample of 384 million BB pairs collected with the BABAR detector at the PEP-Ⅱ asymmetric e + e  ̄ storage ring,we measure branching fractions,direct CP,isospin and lepton-flavor asymmetries for the rare decays B → K (*) l + l ̄ in two di-lepton mass bins above and below the J/ψ resonance.For the B → K* l + l ̄ decay,we also measure the K* longitudinal polarization fraction and the di-lepton forwardbackward asymmetry.