Measurement of Top Quark Polarization in Top-Antitop Events from Proton-Proton Collisions at s√=7 TeV Using the ATLAS Detector

Allison, Lee and Barton, Adam and Borissov, Guennadi and Bouhova-Thacker, Eva and Catmore, James and Chilingarov, Alexandre and Dearnaley, William and Fox, Harald and Grimm, Kathryn and Henderson, Robert and Hughes, Gareth and Jones, Roger William Lewis and Kartvelishvili, Vakhtang and Long, Robin and Love, Peter and Maddocks, Harvey and Smizanska, Maria and Walder, James (2013) Measurement of Top Quark Polarization in Top-Antitop Events from Proton-Proton Collisions at s√=7  TeV Using the ATLAS Detector. Physical review letters, 111 (23). ISSN 1079-7114

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This Letter presents measurements of the polarization of the top quark in top-antitop quark pair events, using 4.7  fb−1 of proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at s√=7  TeV. Final states containing one or two isolated leptons (electrons or muons) and jets are considered. Two measurements of αℓP, the product of the leptonic spin-analyzing power and the top quark polarization, are performed assuming that the polarization is introduced by either a CP conserving or a maximally CP violating production process. The measurements obtained, αℓPCPC=−0.035±0.014(stat)±0.037(syst) and αℓPCPV=0.020±0.016(stat)+0.013−0.017(syst), are in good agreement with the standard model prediction of negligible top quark polarization.

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Physical review letters
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Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. © 2013 CERN, for the ATLAS Collaboration
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24 Jan 2014 09:23
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12 Jul 2020 04:38