The first test of lepton flavor universality between muons and electrons using B+→K+π+π-ℓ+ℓ- (ℓ=e, μ) decays is presented. The measurement is performed with data from proton-proton collisions collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. The ratio of branching fractions between B+→K+π+π-e+e- and B+→K+π+π-μ+μ- decays is measured in the dilepton invariant-mass-squared range 1.1<7.0 GeV2/c4 and is found to be RKππ-1=1.31-0.17+0.18(stat) -0.09+0.12(syst), in agreement with the standard model prediction. The first observation of the B+→K+π+π-e+e- decay is also reported.
Test of Lepton Flavor Universality with B+→K+π+π−ℓ+ℓ− Decays
Argenton, M.;Balboni, A.;Bolzonella, R.;Calabrese, R.;Capriotti, L.;Cavallini, V.;Couturier, B.;Fiorini, M.;Franzoso, E.;Guarise, M.;Kotriakhova, S.;Luppi, E.;Okamura, S.;Pappalardo, L. L.;Passalacqua, B.;Romolini, G.;Tomassetti, L.;
2025
Abstract
The first test of lepton flavor universality between muons and electrons using B+→K+π+π-ℓ+ℓ- (ℓ=e, μ) decays is presented. The measurement is performed with data from proton-proton collisions collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. The ratio of branching fractions between B+→K+π+π-e+e- and B+→K+π+π-μ+μ- decays is measured in the dilepton invariant-mass-squared range 1.1<7.0 GeV2/c4 and is found to be RKππ-1=1.31-0.17+0.18(stat) -0.09+0.12(syst), in agreement with the standard model prediction. The first observation of the B+→K+π+π-e+e- decay is also reported.| File | Dimensione | Formato | |
|---|---|---|---|
|
PhysRevLett.134.181803.pdf
accesso aperto
Descrizione: versione editoriale
Tipologia:
Full text (versione editoriale)
Licenza:
Creative commons
Dimensione
782.88 kB
Formato
Adobe PDF
|
782.88 kB | Adobe PDF | Visualizza/Apri |
I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.


