We report on a measurement of CP-violating asymmetries (A CP) in the Cabibbo-suppressed D0→π +Ï€ - and D0→K +K - decays reconstructed in a data sample corresponding to 5.9fb -1 of integrated luminosity collected by the upgraded Collider Detector at Fermilab. We use the strong decay D *+→D0Ï€ + to identify the flavor of the charmed meson at production and exploit CP-conserving strong ccÌ„ pair production in ppÌ„ collisions. High-statistics samples of Cabibbo-favored D0→K -Ï€ + decays with and without a D *± tag are used to correct for instrumental effects and significantly reduce systematic uncertainties. We measure A CP(D0→π +Ï€ -)=(+0.22±0.24(stat) ±0.11(syst))% and A CP(D0→K +K -)=(-0.24±0.22(stat)±0.09(syst))%, in agreement with CP conservation. These are the most precise determinations from a single experiment to date. Under the assumption of negligible direct CP violation in D0→π +Ï€ - and D0→K +K - decays, the results provide an upper limit to the CP-violating asymmetry in D0 mixing, |ACPind(D0)|<0.13% at the 90% confidence level. © 2012 American Physical Society.

This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; the Swiss National Science Foundation; the A.P. Sloan Foundation; the Bundesministerium fü̈r Bildung und Forschung, Germany; the Korean World Class University Program, the National Research Foundation of Korea; the Science and Technology Facilities Council and the Royal Society, UK; the Russian Foundation for Basic Research; the Ministerio de Ciencia e Innovación, and Programa Consolider-Ingenio 2010, Spain; the Slovak R&D Agency; and the Academy of Finland.

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