Measurement of the mixing at CDF

Paolo Maestro

doi:10.1051/epjconf/20136015014

EPJ

Measurement of the

mixing at CDF

Paolo Maestro^a On behalf of the CDF collaboration

Department of Physics, University of Siena and INFN, via Roma 56, 53100, Siena, Italy

Abstract

We report on the observation of

oscillations by measuring the time-dependent ratio of yields for the rare decay D⁰ → K⁺π⁻ to the favored decay D⁰ → K⁻π⁺ at the Collider Detector at Fermilab (CDF). Using 9.6 fb⁻¹ of integrated luminosity of √s = 1.96 TeV

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.

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