RT Journal Article T1 Test of lepton universality with B0 → K *0 ℓ + ℓ − decays A1 LHCb Collaboration, A1 Adeva Andany, Bernardo A1 Borsato, Martino A1 Chobanova, Veronika A1 Cid Vidal, Xabier A1 Dosil Suárez, Álvaro A1 Fernández Prieto, Antonio A1 García Pardiñas, Julián A1 Lemos Cid, Edgar A1 Lucio Martínez, Miriam A1 Martínez Santos, Diego A1 Plo Casasus, Máximo A1 Prisciandaro, Jessica A1 Ramos Pernas, Miguel A1 Romero Vidal, Antonio A1 Saborido Silva, Juan José A1 Sanmartín Sedes, Brais A1 Santamarina Ríos, Cibrán A1 Vázquez Regueiro, Pablo A1 Vieites Díaz, María A1 Vázquez Sierra, Carlos K1 B physics K1 Branching fraction K1 Hadron-Hadron scattering (experiments) K1 Rare decay AB A test of lepton universality, performed by measuring the ratio of the branching fractions of the B 0 → K *0 μ + μ − and B 0 → K *0 e + e − decays, RK∗0, is presented. The K *0 meson is reconstructed in the final state K + π −, which is required to have an invariant mass within 100 MeV/c 2 of the known K *(892)0 mass. The analysis is performed using proton-proton collision data, corresponding to an integrated luminosity of about 3 fb−1, collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The ratio is measured in two regions of the dilepton invariant mass squared, q 2, to beRK∗0={0.66+−0.110.07(stat)±0.03(syst)for0.045