A measurement of the ratio of branching fractions of the decays B^+→K^+μ^+μ^- and B^+→K^+e^+e^- is presented. The proton-proton collision data used correspond to an integrated luminosity of 5.0  fb^-1 recorded with the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. For the dilepton mass-squared range 1.1<6.0  GeV^2/c^4 the ratio of branching fractions is measured to be R_K=0.846_-0.054^+0.060_-0.014^+0.016, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of R_K to date and is compatible with the standard model at the level of 2.5 standard deviations.

Search for Lepton-Universality Violation in B^+→K^+ℓ^+ℓ^- Decays

Veltri, M;
2019-01-01

Abstract

A measurement of the ratio of branching fractions of the decays B^+→K^+μ^+μ^- and B^+→K^+e^+e^- is presented. The proton-proton collision data used correspond to an integrated luminosity of 5.0  fb^-1 recorded with the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. For the dilepton mass-squared range 1.1<6.0  GeV^2/c^4 the ratio of branching fractions is measured to be R_K=0.846_-0.054^+0.060_-0.014^+0.016, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of R_K to date and is compatible with the standard model at the level of 2.5 standard deviations.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11576/2674246
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