A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector

Barton, Adam Edward and Beattie, Michael and Borissov, Guennadi and Bouhova-Thacker, Evelina Vassileva 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 Maddocks, Harvey and Skinner, Malcolm and Smizanska, Maria and Walder, James William and Wharton, Andy (2016) A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector. European Physical Journal C: Particles and Fields, 76 (5). ISSN 1434-6044

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Abstract

The distribution of particles inside hadronic jets produced in the decay of boosted W and Z bosons can be used to discriminate such jets from the continuum background. Given that a jet has been identified as likely resulting from the hadronic decay of a boosted W or Z boson, this paper presents a technique for further differentiating Z bosons from W bosons. The variables used are jet mass, jet charge, and a b-tagging discriminant. A likelihood tagger is constructed from these variables and tested in the simulation of W′→WZ for bosons in the transverse momentum range 200 GeV <pT<<pT< 400 GeV in √s=8 TeV pp collisions with the ATLAS detector at the LHC. For Z-boson tagging efficiencies of ϵZ=90, 50, and 10%, one can achieve W+ -boson tagging rejection factors (1/ϵW+) of 1.7, 8.3 and 1000, respectively. It is not possible to measure these efficiencies in the data due to the lack of a pure sample of high pT, hadronically decaying Z bosons. However, the modelling of the tagger inputs for boosted W bosons is studied in data using a tt¯-enriched sample of events in 20.3 fb−1 of data at √s=8 TeV. The inputs are well modelled within uncertainties, which builds confidence in the expected tagger performance.

Item Type: Journal Article
Journal or Publication Title: European Physical Journal C: Particles and Fields
Uncontrolled Keywords: /dk/atira/pure/subjectarea/asjc/2200/2201
Subjects:
Departments: Faculty of Science and Technology > Physics
ID Code: 79618
Deposited By: ep_importer_pure
Deposited On: 17 May 2016 15:46
Refereed?: Yes
Published?: Published
Last Modified: 15 Sep 2019 02:07
URI: https://eprints.lancs.ac.uk/id/eprint/79618

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