A test of lepton universality performed by measuring the ratio of the branching fractions of the B-0 -> K*(0)mu(+) mu(-), B-0 -> K*e(+)e(-) decays R-K*0 is presented. The K*(0) meson is reconstructed in the final state K+pi(-) 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, 8 TeV. The ratio is measured in two regions of the dilepton invariant mass squared q(2) to be R-K*0 - \0.66(-0.007)(+0.11)(stat) +/- 0.03(syst) for 0.045 < q(2) < GeV2/c(4) 0.69(-0.07)(+0.11)(stat) +/- 0.05(syst) for 1.1 < q(2) < 6.0 GeV2/c(4). The corresponding 95.4\% confidence level intervals are [0.52 0.89], [0.53 0.94]. The results which represent the most precise measurements of R-K*0 to date are compatible with the Standard Model expectations at the level of 2.1-2.3, 2.4-2.5 standard deviations in the two q(2) regions respectively.

Test of lepton universality with B-0 -> K*(0)l(+)l(-) decays

Bonivento W.;Dettori F.;Lai A.;Manca G.;Oldeman R.;Saitta B.;
2017-01-01

Abstract

A test of lepton universality performed by measuring the ratio of the branching fractions of the B-0 -> K*(0)mu(+) mu(-), B-0 -> K*e(+)e(-) decays R-K*0 is presented. The K*(0) meson is reconstructed in the final state K+pi(-) 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, 8 TeV. The ratio is measured in two regions of the dilepton invariant mass squared q(2) to be R-K*0 - \0.66(-0.007)(+0.11)(stat) +/- 0.03(syst) for 0.045 < q(2) < GeV2/c(4) 0.69(-0.07)(+0.11)(stat) +/- 0.05(syst) for 1.1 < q(2) < 6.0 GeV2/c(4). The corresponding 95.4\% confidence level intervals are [0.52 0.89], [0.53 0.94]. The results which represent the most precise measurements of R-K*0 to date are compatible with the Standard Model expectations at the level of 2.1-2.3, 2.4-2.5 standard deviations in the two q(2) regions respectively.
File in questo prodotto:
File Dimensione Formato  
Aaij2017_Article_TestOfLeptonUniversalityWithB0 (1).pdf

accesso aperto

Tipologia: versione editoriale
Dimensione 2.59 MB
Formato Adobe PDF
2.59 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11584/240327
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 745
  • ???jsp.display-item.citation.isi??? 654
social impact