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oai:recercat.cat:2445/1318402025-12-05T16:49:36Zcom_2072_1057col_2072_478823col_2072_478904col_2072_478917

00925njm 22002777a 4500 dc Abellan Beteta, Carlos author Calvo Gómez, Míriam author Camboni, Alessandro author Comerma Montells, Albert author Garrido Beltrán, Lluís author Graciani Díaz, Ricardo author Graugés Pous, Eugeni author López Asamar, Elias author Oyanguren Campos, Arantza de author Pérez-Calero Yzquierdo, Antonio author Picatoste Olloqui, Eduardo author Potterat, Cédric author Rives Molina, Vicente José author Ruiz, Hugo (Ruiz Pérez) author Ruiz Valls, Pablo author Vázquez Gómez, Ricard author Vilasis-Cardona, Xavier author LHCb Collaboration author 2019-04-08T13:52:59Z 2019-04-08T13:52:59Z 2013-06-21 2019-04-08T13:52:59Z The time-dependent C P asymmetry in B 0 s → J / ψ K + K − decays is measured using p p collision data at √ s = 7     TeV , corresponding to an integrated luminosity of 1.0     fb − 1 , collected with the LHCb detector. The decay-time distribution is characterized by the decay widths Γ L and Γ H of the light and heavy mass eigenstates of the B 0 s − ¯¯¯ B 0 s system and by a C P -violating phase ϕ s . In a sample of 27 617 B 0 s → J / ψ K + K − decays, where the dominant contribution comes from B 0 s → J / ψ ϕ decays, these parameters are measured to be ϕ s = 0.07 ± 0.09 ( stat ) ± 0.01 ( syst )     rad , Γ s ≡ ( Γ L + Γ H ) / 2 = 0.663 ± 0.005 ( stat ) ± 0.006 ( syst )     ps − 1 , and Δ Γ s ≡ Γ L − Γ H = 0.100 ± 0.016 ( stat ) ± 0.003 ( syst )     ps − 1 , corresponding to the single most precise determination of ϕ s , Δ Γ s , and Γ s . The result of performing a combined analysis with B 0 s → J / ψ π + π − decays gives ϕ s = 0.01 ± 0.07 ( stat ) ± 0.01 ( syst )     rad , Γ s = 0.661 ± 0.004 ( stat ) ± 0.006 ( syst )     ps − 1 , and Δ Γ s = 0.106 ± 0.011 ( stat ) ± 0.007 ( syst )     ps − 1 . All measurements are in agreement with the Standard Model predictions. Física de partícules Experiments Violació CP (Física nuclear) Particle physics Experiments CP violation (Nuclear physics) Measurement of CP violation and the B0s meson decay width difference with B0s → J/ψK+K− and B0s → J/ψπ+π− decays