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<𝑞2<7.0 GeV2/𝑐4 and is found to be 𝑅−1𝐾𝜋𝜋=1.31+0.18−0.17(stat) +0.12−0.09(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+ pi + pi -\ell+ \ell- 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 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<𝑞2<7.0 GeV2/𝑐4 and is found to be 𝑅−1𝐾𝜋𝜋=1.31+0.18−0.17(stat) +0.12−0.09(syst), in agreement with the standard model prediction. The first observation of the 𝐵+ →𝐾+𝜋+𝜋−𝑒+𝑒− decay is also reported.
2025
Settore FIS/01 - Fisica Sperimentale
Settore PHYS-01/A - Fisica sperimentale delle interazioni fondamentali e applicazioni
File in questo prodotto:
File Dimensione Formato  
PhysRevLett.134.181803.pdf

accesso aperto

Tipologia: Published version
Licenza: Creative Commons
Dimensione 782.88 kB
Formato Adobe PDF
782.88 kB Adobe PDF

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/11384/164045
Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 4
  • ???jsp.display-item.citation.isi??? 8
  • OpenAlex 2
social impact