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Oxana Smirnova

Oxana Smirnova

Senior Lecturer, Deputy Head of division

Oxana Smirnova

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

Author

  • 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

Summary, in English

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.

Department/s

  • Particle and nuclear physics
  • eSSENCE: The e-Science Collaboration

Publishing year

2016

Language

English

Publication/Series

European Physical Journal C

Volume

76

Issue

5

Document type

Journal article

Publisher

Springer

Topic

  • Subatomic Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1434-6044