The time-dependent CP asymmetry in Bs0→J/ψK+K - decays is measured using pp 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 ΓL and ΓH of the light and heavy mass eigenstates of the Bs0-B̄s0 system and by a CP-violating phase s. In a sample of 27 617 Bs0→J/ψK+K- decays, where the dominant contribution comes from Bs0→J/ψ decays, these parameters are measured to be s=0.07±0.09(stat) ±0.01(syst) rad, Γs≡(ΓL+Γ H)/2=0.663±0.005(stat)±0.006(syst) ps-1, and ΔΓs≡ΓL-ΓH=0. 100±0.016(stat)±0.003(syst) ps-1, corresponding to the single most precise determination of s, ΔΓs, and Γs. The result of performing a combined analysis with Bs0→J/ψπ+π- decays gives s=0.01±0.07(stat)±0.01(syst) rad, Γs= 0.661±0.004(stat)±0.006(syst) ps-1, and ΔΓs=0.106±0.011(stat)±0.007(syst) ps -1. All measurements are in agreement with the Standard Model predictions. © 2013 CERN. Published by the American Physical Society under the terms of the http://creativecommons.org/licenses/by/3.0/ Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Aaij, R., Abellan Beteta, C., Adeva, B., Adinolfi, M., Adrover, C., Affolder, A., … Zvyagin, A. (2013). Measurement of CP violation and the Bs0 meson decay width difference with Bs0→J/ψK+K- and Bs0→J/ψπ +π - Decays. Physical Review D - Particles, Fields, Gravitation and Cosmology, 87(11). https://doi.org/10.1103/PhysRevD.87.112010