We measure the time dependence of the ratio of decay rates
for the rare decay D0 --> K+ pi+- to the Cabibbo-favored decay
D0 --> K- pi++. We use a signal of 12.7 x 103 D0 --> K+ pi+-
decays with proper decay times between 0.75 and 10 mean D0 lifetimes.
The data sample was recorded with the CDF II detector at the Fermilab
Tevatron and corresponds to an integrated luminosity of 1.5 fb-1 for p
anti-p collisions at s**(1/2) = 1.96 TeV. We search for D0 - D-bar0
mixing and measure the mixing parameters to be R_d = (3.04 +/- 0.55)
x 10-3, y' = (8.5 +/- 7.6) x 10-3, and x'2 = (-0.12 +/- 0.35) x 10-3.
We report Bayesian probability contours in the x-2 - y' plane and find
that the data are inconsistent with the no-mixing hypothesis with a
probability equivalent to 3.8 Gaussian standard deviations.
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Updated: Friday, 2008 April 04 13:03:59 CDT automatically from input from carol picciolo