| Summary: | 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.
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