Test of lepton universality with B 0 → K *0 ℓ + ℓ − decays

A test of lepton universality, performed by measuring the ratio of the branching fractions of the B 0 K * 0 + -and B 0 K * 0 e + e -decays, R K * 0 , is presented. The K * 0 meson is reconstructed in the final state K + -, 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 be R K * 0 = 0.66 + 0.11 -0.07 (stat) 0.03 (syst) for 0.045 < q 2 < 1.1 GeV 2 /c 4 , 0.69 + 0.11 -0.07 (stat) 0.05 (syst) for 1.1 < q 2 < 6.0 GeV 2 /c 4 .

Перевод пока недоступен