Tests of Lepton Universality Using B 0 → K 0 S ℓ + ℓ − and B + → K * + ℓ + ℓ − Decays

Tests of lepton universality in B0→K0Sℓ+ℓ− and B+→K*+ℓ+ℓ− decays where ℓ is either an electron or a muon are presented. The differential branching fractions of B0→K0Se+e− and B+→K*+e+e− decays are measured in intervals of the dilepton invariant mass squared. The measurements are performed using proton-proton collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1 . The results are consistent with the standard model and previous tests of lepton universality in related decay modes. The first observation of B0→K0Se+e− and B+→K*+e+e− decays is reported.