Measurement of the charge asymmetry in highly boosted top-quark pair production in √s=8 TeV pp collision data collected by the ATLAS experiment

Barton, Adam Edward and Beattie, Michael and Bertram, Iain Alexander and Borissov, Guennadi and Bouhova-Thacker, Evelina Vassileva and Cheatham, Susan and Dearnaley, William and Fox, Harald and Grimm, Kathryn Ann Tschann and Henderson, Robert Charles William and Hughes, Gareth and Jones, Roger William Lewis and Kartvelishvili, Vakhtang and Long, Robin Eamonn and Love, Peter Allan and Muenstermann, Daniel Matthias Alfred and Skinner, Malcolm and Smizanska, Maria and Walder, James William and Wharton, Andy (2016) Measurement of the charge asymmetry in highly boosted top-quark pair production in √s=8 TeV pp collision data collected by the ATLAS experiment. Physics Letters B, 756. pp. 52-71. ISSN 0370-2693

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Abstract

In the pp → tt¯ process the angular distributions of top and anti-top quarks are expected to present a subtle difference, which could be enhanced by processes not included in the Standard Model. This Letter presents a measurement of the charge asymmetry in events where the top-quark pair is produced with a large invariant mass. The analysis is performed on 20.3 fb−1 of pp collision data at √s = 8 TeV collected by the ATLAS experiment at the LHC, using reconstruction techniques specifically designed for the decay topology of highly boosted top quarks. The charge asymmetry in a fiducial region with large invariant mass of the top-quark pair (mtt¯ > 0.75 TeV) and an absolute rapidity difference of the top and anti-top quark candidates within −2 < |yt| − |yt¯| < 2 is measured to be 4.2 ± 3.2%, in agreement with the Standard Model prediction at next-to-leading order. A differential measurement in three tt¯ mass bins is also presented.

Item Type: Journal Article
Journal or Publication Title: Physics Letters B
Uncontrolled Keywords: /dk/atira/pure/subjectarea/asjc/3100/3106
Subjects:
Departments: Faculty of Science and Technology > Physics
ID Code: 79617
Deposited By: ep_importer_pure
Deposited On: 17 May 2016 15:10
Refereed?: Yes
Published?: Published
Last Modified: 18 Nov 2019 02:48
URI: https://eprints.lancs.ac.uk/id/eprint/79617

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