Measurement of CP asymmetry in D-0 -> K- K+ and D-0 -> pi(-) pi(+) decays

Peter Clarke, Greig Cowan, Stephan Eisenhardt, Franz Muheim, Matthew Needham, Stephen Playfer, LHCb Collaboration

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Time-integrated CP asymmetries in D-0 decays to the final states K- K+ and pi(-) pi(+) are measured using proton-proton collisions corresponding to 3 fb(-1) of integrated luminosity collected at centre-of-mass energies of 7 TeV and 8 TeV. The D-0 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

Delta A(CP) = A(CP)(K- K+) - A(CP)(pi(-) pi(+)) = (+0.14 +/- 0.16 (stat) +/- 0.08 (syst))% .

A measurement of A(CP)(K- K+) is obtained assuming negligible CP violation in charm mixing and in Cabibbo-favoured D decays. It is found to be

A(CP)(K- K+) = (-0.06 +/- 0.15 (stat) +/- 0.10 (syst))% ,

where the correlation coefficient between Delta A(CP) and A(CP)(K- K+) is rho = 0.28. By combining these results, the CP asymmetry in the D-0 -> pi(-) pi(+) channel is A(CP)(pi(-) pi(+)) = (-0.20 +/- 0.19 (stat) +/- 0.10 (syst))%.

Original languageEnglish
Article number041
Pages (from-to)041
Number of pages25
JournalJournal of High Energy Physics
Issue number7
Publication statusPublished - 9 Jul 2014

Keywords / Materials (for Non-textual outputs)

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


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