Measurement of the D0-D0bar mixing at CDF

We report on the observation of D0-D̄0 oscillations by measuring the time-dependent ratio of yields for the rare decay D0 → K+π- to the favored decay D 0 → K-π+ at the Collider Detector at Fermilab (CDF). Using 9.6 fb-1 of integrated luminosity of √s = 1.96 TeV pp̄ collisions recorded in the full CDF Run II, the signals of 7.6 × 106 D0 → K-π+ and 33 × 103 D0 → K+π- decays are reconstructed in D*-tagged events, with proper decay times between 0.75 and 10 mean D0 lifetimes. We measure the mixing parameters x′2 = (0.08 ± 0.18) × 10 -3, y′ = (4.3 ± 4.3) × 10-3, and R D = (3.51 ± 0.35) × 10-3. Our results are consistent with standard model expectations and similar results from proton-proton collisions and exclude the no-mixing hypothesis with a significance equivalent to 6.1 standard deviations. © 2013 Owned by the authors, published by EDP Sciences.