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

G Aad, B. Abbott, J. Abdallah, O Abdinov, R Aben, M Abolins, Torsten Åkesson, Simona Bocchetta, Lene Bryngemark, Caterina Doglioni, Anders Floderus, Anthony Hawkins, Vincent Hedberg, Jenny Ivarsson, Göran Jarlskog, Else Lytken, Ulf Mjörnmark, Oxana Smirnova, Oleksandr Viazlo, ATLAS Collaboration

Research output: Contribution to journalArticlepeer-review

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< 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. © 2016, CERN for the benefit of the ATLAS collaboration.
Original languageEnglish
JournalEuropean Physical Journal C
Volume76
Issue number5
DOIs
Publication statusPublished - 2016

Bibliographical note

Cited By :1

Export Date: 23 May 2018

Subject classification (UKÄ)

  • Subatomic Physics

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