Observation of D0-D0 Mixing Using the CDF II Detector
Full CDF Run II dataset: 9.6 fb-1
S. Behari1, P. Karchin2, P. Maestro3, M. Mattson2
1 Fermilab,
2 Wayne State University,
3 University of Siena and INFN, Italy
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We measure the time dependence of the ratio of decay rates for the rare
decay
D0 → K+ π-
to the Cabibbo-favored decay
D0 → K- π+.
The charge conjugate decays are included. A signal of 33 × 103
D*+ → π+ D0,
D0 → K+ π-
decays is obtained 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 9.6 fb-1 for p-pbar
collisions at sqrt(s) = 1.96 TeV. Assuming CP conservation, we search for
D0-D0 mixing and measure the mixing parameters to be
RD = (3.51 ± 0.35) 10-3,
y' = (4.3 ± 4.3) 10-3, and
x'2 = (0.08 ± 0.18) 10-3.
We report Bayesian probability contours in the x'2-y' plane
and find that the no-mixing hypothesis is excluded with a probability
equivalent to 6.1 Gaussian standard deviations, providing an observation of
D0-D0 mixing from a single experiment.
D*+ WS/RS Ratio vs proper decay time
EPS PDF
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Bayesian probability intervals in (x'2,y') space
EPS PDF
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Mixing parameters result
EPS PDF
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Documentation
Supporting Plots
- D0 signal:
- D*+ signal:
- Secondary (B) contribution:
- [PNG,
EPS,
PDF] Impact parameter
(d0) for RS D*+
- [PNG,
EPS,
PDF] Secondary fraction
(fB), the fraction of non-prompt RS D*+ decays
- Statistical interpretation:
- [PNG,
EPS,
PDF] A frequentist p-value test
comparing χ2 difference between mixing and no-mixing fits
- [PNG,
EPS,
PDF] Comparison of
(x'2,y') contours between experiments.
- Selection cuts:
- [PNG,
EPS,
PDF] Right-sign vs
Wrong-sign Kπ mass before
signal selection
- [PNG,
EPS,
PDF] Right-sign vs
Wrong-sign Kπ mass illustrating
the opposite-mass-assignment requirement for Wrong-sign signal selection
- [PNG,
EPS,
PDF] Right-sign Kπ mass BEFORE signal selection
[PNG,
EPS,
PDF] Right-sign Kπ mass AFTER signal selection
- [PNG,
EPS,
PDF] Wrong-sign Kπ mass BEFORE signal selection
[PNG,
EPS,
PDF] Wrong-sign Kπ mass AFTER signal selection
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Last modified: 04/08/2013