Abstract

We provide the most up-to-date predictions for the top-quark charge asymmetry A_C at the LHC with a centre-of-mass energy of 8 TeV. Our result is accurate at the NNLO level in the strong interactions and at the complete-NLO level in both the strong and electroweak interactions. We present results for the inclusive A_C, several differential asymmetries as well as the P_{T,tt} and M_{tt} cumulative asymmetries. Similarly to the Tevatron forward-backward asymmetry A_FB, both NNLO QCD and NLO EW corrections to A_C are found to be significant. The inclusion of higher-order corrections reduces the residual scale dependence in the predicted A_C. The pattern of higher-order corrections indicates good perturbative control over these observables. We conclude that at present there is nearly uniform agreement between Standard Model predictions and LHC measurements across all A_C-related observables. All previously published differential A_FB predictions at the Tevatron are updated to the same accuracy.

Highlights

  • The charge asymmetry in top-quark pair production at hadron colliders has attracted a lot of interest in the last decade

  • We systematically account for NNLO QCD and complete-NLO corrections

  • We find that both the NNLO QCD and EW corrections have a large impact on the predicted charge asymmetry, both inclusively and differentially

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Summary

INTRODUCTION

The charge asymmetry in top-quark pair production at hadron colliders has attracted a lot of interest in the last decade. [25,26,27,28] and, unlike NLO EW, denotes the complete set of SM corrections For tt production this corresponds to the NLO QCD at Oðα3sÞ, the NLO electroweak (EW) at Oðαα2SÞ as well as the contributions at Oðα2αSÞ and Oðα3Þ together with the LO ones at OðααSÞ and Oðα2Þ. As was established at the Tevatron effects of both QCD and EW origin are numerically significant and have to be included in any realistic comparison between LHC measurements and SM theory. We use this opportunity to update earlier NNLO QCD differential Tevatron AFB predictions [23,24] by merging them consistently with the complete-NLO predictions

SETUP OF THE CALCULATION
Inclusive asymmetry
Differential asymmetry
NNLO QCD
NNLO QCD 1
Cumulative asymmetry
UPDATED TEVATRON AFB PREDICTIONS
Findings
SUMMARY
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