Measurement of CP asymmetry in D 0 → K − K + decays

Journal article

A measurement of the time-integrated CP asymmetry in the Cabibbo-suppressed decay D0 → K−K+ is performed using pp collision data, corresponding to an integrated luminosity of 3 fb^−1 , collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV. The flavour of the charm meson at production is determined from the charge of the pion in D*+ → D0π+ and D*− → D‾0π− decays. The time-integrated CP asymmetry ACP (K−K+) is obtained assuming negligible CP violation in charm mixing and in Cabibbo-favoured D0 → K−π+, D+ → K−π+π+ and D+ → K‾0π+ decays used as calibration channels. It is found to be A CP(K−K+) = (0.14±0.15 (stat)±0.10 (syst))%. A combination of this result with previous LHCb measurements yields A CP (K − K + )=(0.04±0.12 (stat)±0.10 (syst))%,A CP (π−π+) = (0.07±0.14 (stat)±0.11 (syst))%. These are the most precise measurements from a single experiment. The result for A CP(K−K+) is the most precise determination of a time-integrated CP asymmetry in the charm sector to date, and neither measurement shows evidence of CP asymmetry.

Authors: Aaij, R; Adeva, B; Adinolfi, M; Evans, T; Gandini, P

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Physics Letters B
• Volume: 767
• Pages: 177-187
• Publication date: 2017-02-01
• Acceptance date: 2017-01-27
• DOI: 10.1016/j.physletb.2017.01.061
• EISSN: 1873-2445
• ISSN: 0370-2693
• Keywords: hep-ex