Leptonic Asymmetry in tT Production

Leptonic Asymmetry in tt Production

Authors
Dan Amidei, Myron Campbell, Ryan Edgar, Dave Mietlicki
Monica Tecchio, Jon Wilson, Tom Wright, Thomas A Schwarz
University of Michigan

Joey Huston
Michigan State University

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Public note: CDF10975

CONTENTS

Abstract
Figures
Tables

ABSTRACT

We measure the asymmetry of the lepton in semileptonic tt decays in the full Run II sample of 9.4fb^-1. We develop a new technique to correct for the incomplete lepton acceptance and derive a parton-level asymmetry. The result of 0.094 +0.032 -0.029 is approximately 2σ above the current Standard Model NLO prediction of A_fb^lep=0.036.

Figures (Monte Carlo)
Fig. 1 pdf Generator-level qy_l. The vertical lines at \|qy_l\|=1.25 indicate the limits of the lepton acceptance.	Fig. 2a pdf The symmetric part of qy_l at generator-level.	Fig. 2b pdf A_fb^lep(qy_l) at generator-level.
Figures (Data Results)
Fig. 4 pdf qy_l in the antitag control region.	Fig. 5 pdf p_T of the lepton.	Fig. 6a pdf qy_l in the data compared to powheg and the predicted background.	Fig. 6b pdf qy_l after background subtraction, compared to powheg.
Fig. 7a pdf The symmetric part of qy_l after background subtraction, compared to powheg.	Fig. 7b pdf A_fb^lep(qy_l) after background subtraction, compared to powheg.	Fig. 8 pdf A(qy_l) after acceptance-correction, with fits

Tables
Tbl. 1 pdf tex Generator-Level Monte Carlo asymmetries and polarizations.	Tbl. 2 pdf tex True Monte Carlo asymmetries compared to mean extrapolated results for 10,000 simulated experiments using the data statistics.
Tbl. 3 pdf tex Sample composition as estimated by Method 2.	Tbl. 4 pdf tex Comparison of the predicted and measured asymmetries in the antitag sample.
Tbl. 5 pdf tex Uncertainties on the fully-extrapolated measurement.	Tbl. 6 pdf tex Summary of the resulting asymmetries when the sample is divided by either lepton charge or lepton type. Also included is the inclusive result.
Tbl. 7 pdf tex Measured asymmetries at each level of correction compared to the prediction of powheg and backgrounds.