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Göran Jarlskog

Göran Jarlskog

Professor emeritus

Göran Jarlskog

Measurement of τ polarisation in Z/ γ∗→ ττ decays in proton–proton collisions at √s=8 TeV with the ATLAS detector

Author

  • M Aaboud
  • G Aad
  • B. Abbott
  • O Abdinov
  • B Abeloos
  • S. H. Abidi
  • Torsten Åkesson
  • Simona Bocchetta
  • Caterina Doglioni
  • Vincent Hedberg
  • Göran Jarlskog
  • Charles Kalderon
  • Edgar Kellermann
  • Else Lytken
  • Katja Mankinen
  • Ulf Mjörnmark
  • Ruth Pöttgen
  • Trine Poulsen
  • Oxana Smirnova
  • Oleksandr Viazlo

Summary, in English

This paper presents a measurement of the polarisation of τ leptons produced in Z/ γ∗→ ττ decays which is performed with a dataset of proton—proton collisions at s=8 TeV, corresponding to an integrated luminosity of 20.2 fb- 1 recorded with the ATLAS detector at the LHC in 2012. The Z/ γ∗→ ττ decays are reconstructed from a hadronically decaying τ lepton with a single charged particle in the final state, accompanied by a τ lepton that decays leptonically. The τ polarisation is inferred from the relative fraction of energy carried by charged and neutral hadrons in the hadronic τ decays. The polarisation is measured in a fiducial region that corresponds to the kinematic region accessible to this analysis. The τ polarisation extracted over the full phase space within the Z/ γ∗ mass range of 66 <mZ/ 116 GeV is found to be Pτ= - 0.14 ± 0.02 (stat) ± 0.04 (syst). It is in agreement with the Standard Model prediction of Pτ= - 0.1517 ± 0.0019 , which is obtained from the ALPGEN event generator interfaced with the PYTHIA 6 parton shower modelling and the TAUOLA τ decay library. © 2018, CERN for the benefit of the ATLAS collaboration.

Department/s

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

Publishing year

2018

Language

English

Publication/Series

European Physical Journal C

Volume

78

Issue

2

Document type

Journal article

Publisher

Springer

Topic

  • Subatomic Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1434-6044