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*0 meson is reconstructed in the final state K+π−, which is required to have an invariant mass within 100 MeV/c2 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, 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 q2 regions, respectively.[Figure not available: see fulltext.]. © 2017, The Author(s).

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

Graverini, E.;Punzi, G.;Stracka, 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*0 meson is reconstructed in the final state K+π−, which is required to have an invariant mass within 100 MeV/c2 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, 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 q2 regions, respectively.[Figure not available: see fulltext.]. © 2017, The Author(s).
2017
The LHCb, Collaboration; Aaij, R.; Adeva, B.; Adinolfi, M.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; ...espandi
File in questo prodotto:
File Dimensione Formato  
JHEP_08_2017_055.pdf

accesso aperto

Tipologia: Versione finale editoriale
Licenza: Creative commons
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/11568/906089
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 746
  • ???jsp.display-item.citation.isi??? 657
social impact