The first test of lepton flavor universality between muons and electrons using Bþ → Kþπþπ−lþl−(l ¼ 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 Bþ → Kþπþπ−eþe−and Bþ → Kþπþπ−μþμ− decays is measured in the dilepton invariant-mass-squared range 1.1 < q2 < 7.0 GeV2=c4 and is found to be R−1Kππ ¼ 1.31þ0.18 −0.17 ðstatÞ þ0.12 −0.09 ðsystÞ, in agreement with the standard model prediction. The first observation of the Bþ → Kþπþπ−eþe− decay is also reported.

Test of Lepton Flavor Universality with B+ → K+ π + π −l+l− Decays

Bassi G.
Membro del Collaboration Group
;
Kleijne N.
Membro del Collaboration Group
;
Morello M. J.
Membro del Collaboration Group
;
Passaro D.
Membro del Collaboration Group
;
Pica L.
Membro del Collaboration Group
;
Riccardi D.
Membro del Collaboration Group
;
2025

Abstract

The first test of lepton flavor universality between muons and electrons using Bþ → Kþπþπ−lþl−(l ¼ 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 Bþ → Kþπþπ−eþe−and Bþ → Kþπþπ−μþμ− decays is measured in the dilepton invariant-mass-squared range 1.1 < q2 < 7.0 GeV2=c4 and is found to be R−1Kππ ¼ 1.31þ0.18 −0.17 ðstatÞ þ0.12 −0.09 ðsystÞ, in agreement with the standard model prediction. The first observation of the Bþ → Kþπþπ−eþe− decay is also reported.
2025
Settore FIS/01 - Fisica Sperimentale
Settore PHYS-01/A - Fisica sperimentale delle interazioni fondamentali e applicazioni
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/164045
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