The CP asymmetry and branching fraction of the Cabibbo-Kobayashi-Maskawa-suppressed decay B+ → J/ψ π+ are precisely measured relative to the favoured decay B+ → J/ψ K+, using a sample of proton-proton collision data corresponding to an integrated luminosity of 5.4 fb^−1 recorded at center-of-mass energy of 13 TeV during 2016-2018. The results of the CP asymmetry difference and branching fraction ratio are ΔA^CP ≡ A^CP(B+ → J/ψ π+) − A^CP(B+ → J/ψ K+) = (1.29 ± 0.49 ± 0.08) × 10^−2, R_π/K ≡ [B(B+ → J/ψ π+)/B(B+ → J/ψ K+)] = (3.852 ± 0.022 ± 0.018) × 10^−2, where the first uncertainties are statistical and the second are systematic. A combination with previous LHCb results based on data collected at 7 and 8 TeV in 2011 and 2012 yields ΔA^CP = (1.42 ± 0.43 ± 0.08) × 10^−2 and R_π/K = (3.846 ± 0.018 ± 0.018) × 10^−2. The combined ΔA^CP value deviates from zero by 3.2 standard deviations, providing the first evidence for direct CP violation in the amplitudes of beauty decays to charmonium final states.

Aaij, R., Abdelmotteleb, A. . ., Abellan Beteta, C., Abudinén, F., Ackernley, T., Adefisoye, A. ., et al. (2025). First Evidence for Direct CP Violation in Beauty to Charmonium Decays. PHYSICAL REVIEW LETTERS, 134(10), 1-13 [10.1103/physrevlett.134.101801].

First Evidence for Direct CP Violation in Beauty to Charmonium Decays

Carbone, A.;Ferrari, F.;Galli, D.;Patrignani, C.;Spedicato, E.;Villa, A.;Zenesini, F.;
2025

Abstract

The CP asymmetry and branching fraction of the Cabibbo-Kobayashi-Maskawa-suppressed decay B+ → J/ψ π+ are precisely measured relative to the favoured decay B+ → J/ψ K+, using a sample of proton-proton collision data corresponding to an integrated luminosity of 5.4 fb^−1 recorded at center-of-mass energy of 13 TeV during 2016-2018. The results of the CP asymmetry difference and branching fraction ratio are ΔA^CP ≡ A^CP(B+ → J/ψ π+) − A^CP(B+ → J/ψ K+) = (1.29 ± 0.49 ± 0.08) × 10^−2, R_π/K ≡ [B(B+ → J/ψ π+)/B(B+ → J/ψ K+)] = (3.852 ± 0.022 ± 0.018) × 10^−2, where the first uncertainties are statistical and the second are systematic. A combination with previous LHCb results based on data collected at 7 and 8 TeV in 2011 and 2012 yields ΔA^CP = (1.42 ± 0.43 ± 0.08) × 10^−2 and R_π/K = (3.846 ± 0.018 ± 0.018) × 10^−2. The combined ΔA^CP value deviates from zero by 3.2 standard deviations, providing the first evidence for direct CP violation in the amplitudes of beauty decays to charmonium final states.
2025
Aaij, R., Abdelmotteleb, A. . ., Abellan Beteta, C., Abudinén, F., Ackernley, T., Adefisoye, A. ., et al. (2025). First Evidence for Direct CP Violation in Beauty to Charmonium Decays. PHYSICAL REVIEW LETTERS, 134(10), 1-13 [10.1103/physrevlett.134.101801].
Aaij, R.; Abdelmotteleb, A.  S.  W.; Abellan Beteta, C.; Abudinén, F.; Ackernley, T.; Adefisoye, A.  A.; Adeva, B.; Adinolfi, M.; Adlarson, P.; Agapop...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/1008086
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