Precision measurement of CP violation in B0S → J/ ΨK+K- decays

LHCb Collaboration, R. Aaij, B. Adeva, M. Adinolfi, A. Affolder, Z. Ajaltouni, S. Akar, J. Albrecht, F. Alessio, M. Alexander, S. Ali, G. Alkhazov, P. Alvarez Cartelle, A. A. Alves, S. Amato, S. Amerio, Y. Amhis, L. An, L. Anderlini, J. AndersonR. Andreassen, M. Andreotti, J. E. Andrews, R. B. Appleby, O. Aquines Gutierrez, F. Archilli, A. Artamonov, M. Artuso, E. Aslanides, G. Auriemma, M. Baalouch, S. Bachmann, J. J. Back, A. Badalov, C. Baesso, W. Baldini, R. J. Barlow, C. Barschel, S. Barsuk, S. Bifani, N. Farley, P. Griffith, P. Ilten, I. R. Kenyon, C. Lazzeroni, A. Mazurov, J. McCarthy, C. J. Parkinson, L. Pescatore, D. Popov, N. K. Watson

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The time-dependent CP asymmetry in B0→ J/ψK+K- decays is measured using pp collision data, corresponding to an integrated luminosity of 3.0 fb-1, collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. In a sample of 96 000 B0→ J/ψK+K- decays, the CP-violating phase φs is measured, as well as the decay widths ΓL and ΓH of the light and heavy mass eigenstates of the B0s-B¯0s system. The values obtained are φs=-0.058±0.049±0.006 rad, Γs≡(ΓLH)/2=0.6603±0.0027±0.0015 ps-1, and ΔΓs≡ΓLH=0.0805±0.0091±0.0032 ps-1, where the first uncertainty is statistical and the second, systematic. These are the most precise single measurements of those quantities to date. A combined analysis with B0→ J/ψπ+π- decays gives φs=-0.010±0.039 rad. All measurements are in agreement with the standard model predictions. For the first time, the phase φs is measured independently for each polarization state of the K+K- system and shows no evidence for polarization dependence.

Original languageEnglish
Article number041801
Number of pages9
JournalPhysical Review Letters
Issue number4
Publication statusPublished - 30 Jan 2015

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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