A test of lepton universality, performed by measuring the ratio of the branching fractions of the B0→ K*0μ+μ−and B0→ K*0e+e−decays, RK*0, is presented. The K*0meson is reconstructed in the final state K+π−, which is required to have an invariant mass within 100 MeV/c2of the known K*(892)0mass. 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, q2, to be (Formula presented.) The corresponding 95.4% confidence level intervals are [0.52, 0.89] and [0.53, 0.94]. The results, which represent the most precise measurements of RK*0 to date, are compatible with the Standard Model expectations at the level of 2.1–2.3 and 2.4–2.5 standard deviations in the two q2regions, respectively.[Figure not available: see fulltext.].

Test of lepton universality with B0->K*0 l+ l- decays

De Serio, M.;Pappagallo, M.;Simone, S.;
2017-01-01

Abstract

A test of lepton universality, performed by measuring the ratio of the branching fractions of the B0→ K*0μ+μ−and B0→ K*0e+e−decays, RK*0, is presented. The K*0meson is reconstructed in the final state K+π−, which is required to have an invariant mass within 100 MeV/c2of the known K*(892)0mass. 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, q2, to be (Formula presented.) The corresponding 95.4% confidence level intervals are [0.52, 0.89] and [0.53, 0.94]. The results, which represent the most precise measurements of RK*0 to date, are compatible with the Standard Model expectations at the level of 2.1–2.3 and 2.4–2.5 standard deviations in the two q2regions, respectively.[Figure not available: see fulltext.].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/215617
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