A test of lepton flavor universality in B ± → K ± μ + μ − and B ± → K ± e + e − decays, as well as a measurement of differential and integrated branching fractions of a nonresonant B ± → K ± μ + μ − decay are presented. The analysis is made possible by a dedicated data set of proton-proton collisions at s = 13 TeV recorded in 2018, by the CMS experiment at the LHC, using a special high-rate data stream designed for collecting about 10 billion unbiased b hadron decays. The ratio of the branching fractions B ( B ± → K ± μ + μ − ) to B ( B ± → K ± e + e − ) is determined from the measured double ratio R ( K ) of these decays to the respective branching fractions of the B ± → J / ψ K ± with J / ψ → μ + μ − and e + e − decays, which allow for significant cancellation of systematic uncertainties. The ratio R ( K ) is measured in the range 1.1 < q 2 < 6.0 GeV 2 , where q is the invariant mass of the lepton pair, and is found to be R ( K ) = 0.78 − 0.23 + 0.47 , in agreement with the standard model expectation R ( K ) ≈ 1 . This measurement is limited by the statistical precision of the electron channel. The integrated branching fraction in the same q 2 range, B ( B ± → K ± μ + μ − ) = ( 12.42 ± 0.68 ) × 10 − 8 , is consistent with the present world-average value and has a comparable precision.

Hayrapetyan, A., Tumasyan, A., Adam, W., Andrejkovic, J., Bergauer, T., Chatterjee, S., et al. (2024). Test of lepton flavor universality in B ± → K ± μ + μ − and B ± → K ± e + e − decays in proton-proton collisions at s = 13 TeV. REPORTS ON PROGRESS IN PHYSICS, 87(7) [10.1088/1361-6633/ad4e65].

Test of lepton flavor universality in B ± → K ± μ + μ − and B ± → K ± e + e − decays in proton-proton collisions at s = 13 TeV

Boldrini G.;Brivio F.;Cetorelli F.;De Guio F.;Dinardo M. E.;Ghezzi A.;Govoni P.;Guzzi L.;Lucchini M. T.;Malberti M.;Moroni L.;Paganoni M.;Pinolini B. S.;Ragazzi S.;de Fatis T. T.;Zuolo D.;
2024

Abstract

A test of lepton flavor universality in B ± → K ± μ + μ − and B ± → K ± e + e − decays, as well as a measurement of differential and integrated branching fractions of a nonresonant B ± → K ± μ + μ − decay are presented. The analysis is made possible by a dedicated data set of proton-proton collisions at s = 13 TeV recorded in 2018, by the CMS experiment at the LHC, using a special high-rate data stream designed for collecting about 10 billion unbiased b hadron decays. The ratio of the branching fractions B ( B ± → K ± μ + μ − ) to B ( B ± → K ± e + e − ) is determined from the measured double ratio R ( K ) of these decays to the respective branching fractions of the B ± → J / ψ K ± with J / ψ → μ + μ − and e + e − decays, which allow for significant cancellation of systematic uncertainties. The ratio R ( K ) is measured in the range 1.1 < q 2 < 6.0 GeV 2 , where q is the invariant mass of the lepton pair, and is found to be R ( K ) = 0.78 − 0.23 + 0.47 , in agreement with the standard model expectation R ( K ) ≈ 1 . This measurement is limited by the statistical precision of the electron channel. The integrated branching fraction in the same q 2 range, B ( B ± → K ± μ + μ − ) = ( 12.42 ± 0.68 ) × 10 − 8 , is consistent with the present world-average value and has a comparable precision.
Articolo in rivista - Articolo scientifico
B meson; B physics; b to sll transitions; CMS; lepton flavor universality;
English
3-lug-2024
2024
87
7
077802
open
Hayrapetyan, A., Tumasyan, A., Adam, W., Andrejkovic, J., Bergauer, T., Chatterjee, S., et al. (2024). Test of lepton flavor universality in B ± → K ± μ + μ − and B ± → K ± e + e − decays in proton-proton collisions at s = 13 TeV. REPORTS ON PROGRESS IN PHYSICS, 87(7) [10.1088/1361-6633/ad4e65].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/593961
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