Measurement of CP asymmetry in D0 → K- K+ and D0 → π-π+ decays

LHCb Collaboration, R. Aaij, B. Adeva, M. Adinolfi, A. Affolder, Z. Ajaltouni, 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. Anderson, R. AndreassenM. 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, V. Balagura, W. Baldini, R. J. Barlow, C. Barschel, S. Barsuk, W. Barter, 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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Time-integrated CP asymmetries in D0 decays to the final states K- K+ and π- π+ are measured using proton-proton collisions corresponding to 3fb-1 of integrated luminosity collected at centre-of-mass energies of 7 TeV and 8 TeV. The D0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon is used to determine the initial flavour of the charm meson. The difference in CP asymmetries between the two final states is measured to be Δ ACP = ACP (K- K+)  - ACP- π+) = (+ 0.14 ± 0.16 (stat) ± 0.08 (syst)) %. A measurement of ACP (K- K+) is obtained assuming negligible CP violation in charm mixing and in Cabibbo-favoured D decays. It is found to be ACP (K- K+) = (- 0.06 ± 0.15 (stat) ± 0.10 (syst)) %, where the correlation coefficient between ΔACP and ACP (K- K+) is ρ = 0.28. By combining these results, the CP asymmetry in the D0 → π- π+ channel is ACP- π+) = (-0.20 ± 0.19 (stat) ± 0.10 (syst))%. 

Original languageEnglish
Article number41
Number of pages25
JournalJournal of High Energy Physics
Issue number7
Publication statusPublished - 9 Jul 2014


  • Charm physics
  • CP violation
  • Flavor physics
  • Hadron-Hadron Scattering

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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