# Measurement of the Forward-Backward Asymmetry of $$\ttbar$$ Production in the Dilepton Final State

Authors
Ziqing Hong, Dave Toback, and Jon S. Wilson
Texas A&M University

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### Public note: CDF11161

We measure the forward-backward asymmetry of the top quark--antiquark pair events ($$\afbtt$$) in the dilepton final state with the full CDF run II data, corresponding to an integrated luminosity of $$9.1~\fbm$$. The inclusive $$\afbtt$$ is $$\afbtt = 0.12 \pm 0.11 (\stat) \pm 0.07 (\syst) = 0.12 \pm 0.13$$. This result is consistent with the NNLO standard model expectation of $$\afbtt = 0.095 \pm 0.007$$ and the CDF measurement in the lepton + jets final state of $$\afbtt = 0.164 \pm 0.047$$. We also measure the $$\afbtt$$ as a function of the rapidity difference of the top pairs ($$\dy$$). The results are $$\afbtt(|\dy|<0.5)=0.12\pm0.33(\stat)\pm0.20(\syst) = 0.12\pm0.39$$ and $$\afbtt(|\dy|>0.5)=0.13\pm0.13(\stat)\pm0.11(\syst)=0.13\pm0.17$$, which can be compared to the predictions from the Powheg Monte Carlo at 0.017 and 0.081, respectively. The slope of the $$\afbtt$$ vs. $$|\dy|$$ is estimated to be $$\alpha=0.14\pm0.15$$, consistent with the NNLO SM prediction.

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