Measurement of the top quark pair production charge asymmetry in proton-proton collisions at \( \sqrt{s} \) = 7 TeV using the ATLAS detector

Abstract

This paper presents a measurement of the top quark pair (\( t\overline{t} \)) production charge asymmetry A C using 4.7 fb−1 of proton-proton collisions at a centre-of-mass energy \( \sqrt{s} \) = 7 TeV collected by the ATLAS detector at the LHC. A \( t\overline{t} \)-enriched sample of events with a single lepton (electron or muon), missing transverse momentum and at least four high transverse momentum jets, of which at least one is tagged as coming from a b-quark, is selected. A likelihood fit is used to reconstruct the \( t\overline{t} \) event kinematics. A Bayesian unfolding procedure is employed to estimate A C at the parton-level. The measured value of the \( t\overline{t} \) production charge asymmetry is A C = 0.006 ± 0.010, where the uncertainty includes both the statistical and the systematic components. Differential A C measurements as a function of the invariant mass, the rapidity and the transverse momentum of the \( t\overline{t} \) system are also presented. In addition, A C is measured for a subset of events with large \( t\overline{t} \) velocity, where physics beyond the Standard Model could contribute. All measurements are consistent with the Standard Model predictions.

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ArXiv ePrint: 1311.6724

Deceased (V. V. Ammosov, E. Arik, W. Blum, A. Bogouch, H. M. Braun, C. Caso, V. Chernyatin, Y. Doi, B. A. Dolgoshein, A. A. Komar, M. J. Losty, K. W. McFarlane, S. V. Mouraviev, F. Pastore, G. Sauvage, A. N. Sisakyan, P. Stavina, I. Stumer, R. P. Thun, W. Willis)

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The ATLAS collaboration., Aad, G., Abajyan, T. et al. Measurement of the top quark pair production charge asymmetry in proton-proton collisions at \( \sqrt{s} \) = 7 TeV using the ATLAS detector. J. High Energ. Phys. 2014, 107 (2014). https://doi.org/10.1007/JHEP02(2014)107

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Keywords

  • Hadron-Hadron Scattering
  • Top physics