Measurement of the Forward Backward Asymmetry in Top Pair Production in the Dilepton Decay Channel using 5.1 fb^-1

Authors

Yuji Takeuchi	Yen-Chu Chen	Jaroslav Antos
University of Tsukuba	Academia Sinica	Slovak Academy of Science

Chang-Seong Moon	Youngdo Oh	Hyunsoo Kim	Thomas Schwarz
Seoul National University, Korea	Kyungpook National University, Korea	Chonbuk National University	University of California, Davis

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Conference Note

We report on a measurement of the inclusive forward-backward asymmetry in tt production in the dilepton channel using 334 dilepton candidates collected in 5.1 fb^-1 of collected data. The production angle of top is measured using the rapidity difference between top and anti-top quarks (Δy_t). For the reconstructed asymmetry, without corrections:
A_{fb (data)} = 0.14 ± 0.05_stat

The measurement is corrected for backgrounds, detector acceptance, and resolution effects, which serve to bias and/or dilute the measurement. After subtracting the predicted background contribution, the and the asymmetry of the background subtracted Δy_t is found to be:

A_{fb (data)} = 0.21 ± 0.07_stat ± 0.02_bkg-shape

Finally, detector and acceptance effects are corrected by a fit, assuming a linear dependence of the production angle on the underlying asymmetry. The fully corrected measured asymmetry is:

A_{fb (corrected)} = 0.42 ± 0.15_stat ± 0.05_syst

which is to be compared to the standard model prediction, A_{fb (theory)} = 0.06 ± 0.01_.