Dan Amidei, Myron Campbell, Ryan Edgar, Dave Mietlicki, Monica Tecchio, Jon S. Wilson, and Tom Wright
University of Michigan
Thomas A Schwarz
FNAL
Joey Huston
Michigan State University
Ziqing Hong, Dave Toback, and Jon S. Wilson
Texas A&M University
We present a combination of the measurements of the \(\afbtt\) from CDF with lepton+jets and dilepton final states using the full dataset collected by the CDF II detector. The improved measurement is \(\afbtt = 0.160\pm0.045\). The combined result is consistent with the NNLO SM calculation at \(\afbtt = 0.095 \pm 0.007\). The differential \(\afbtt\) as a function of \(|\dy|\) in the two final states are also combined with a simultaneous fit, yielding a result of \(\alpha=0.227\pm0.057\), which is \(2\sigma\) higher than the NNLO SM calculation.
1 | \[\afbtt = \frac{N(\dy > 0) - N(\dy < 0)}{N(\dy > 0) + N(\dy < 0)}\] \[\dy=y_{t}-y_{\bar{t}}\] |
\(\ttbar\rightarrow\ell\nu+jets\): \(\ttbar\rightarrow\ell^{+}\ell^{-}+jets+\MET\): |
|
Inclusive \(\afbtt\) | |||
2 |
![]() |
Table of uncertainties of \(\afbtt\) measurement with the lepton+jets and the dilepton final states. In the column of correlation, "0" indicates no correlation and "1" indicates fully positive correlation. |
|
3 |
![]() |
The combined \(\afbtt\):
\[\afbtt = 0.160\pm0.045\]
The weight of the lepton+jets result is 91%, and the weight of the dilepton result is 9%. The correlation between the two results is 10%. |
|
Differential \(\afbtt\) vs. \(|\dy|\) | |||
4 |
![]() |
The best fit of \(\afbtt=\alpha\cdot|\dy|\) with measurements from both lepton+jets and dilepton final states. All correlations are taken into account. The bin centroids, differential \(\afbtt\), as well as eigenvalues and eigenvectors of the covariance matrix is shown. |
|
5 |
![]() |
The best fit result is
\[\alpha = 0.227\pm0.057\]
This result is \(2\sigma\) larger than the NNLO SM calculation |
|
6 |
![]() |
Comparison of the slope \(\alpha\) of \(\afbtt\) vs. \(|\dy|\) from various measurements. |