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

Aaboud, M; Aad, G; Abbott, B.; Abdinov, O; Abeloos, B; Abidi, S. H.; Åkesson, Torsten LU ; Bocchetta, Simona LU ; Doglioni, Caterina LU and Hedberg, Vincent LU , et al. (2018) In European Physical Journal C 78(2).
Abstract
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... (More)
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. (Less)
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European Physical Journal C
volume
78
issue
2
publisher
Springer
external identifiers
  • scopus:85042560791
ISSN
1434-6044
DOI
10.1140/epjc/s10052-018-5619-1
language
English
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yes
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b4246f08-bfdc-4e76-a802-c406dc6c9e15
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2018-03-08 15:01:33
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2018-05-29 11:25:21
@article{b4246f08-bfdc-4e76-a802-c406dc6c9e15,
  abstract     = {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 &lt;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.},
  articleno    = {163},
  author       = {Aaboud, M and Aad, G and Abbott, B. and Abdinov, O and Abeloos, B and Abidi, S. H. and Åkesson, Torsten and Bocchetta, Simona and Doglioni, Caterina and Hedberg, Vincent and Jarlskog, Göran and Kalderon, Charles and Kellermann, Edgar and Lytken, Else and Mankinen, Katja and Mjörnmark, Ulf and Pöttgen, Ruth and Poulsen, Trine and Smirnova, Oxana and Viazlo, Oleksandr and , },
  issn         = {1434-6044},
  language     = {eng},
  number       = {2},
  publisher    = {Springer},
  series       = {European Physical Journal C},
  title        = {Measurement of τ polarisation in Z/ γ∗→ ττ decays in proton–proton collisions at √s=8 TeV with the ATLAS detector},
  url          = {http://dx.doi.org/10.1140/epjc/s10052-018-5619-1},
  volume       = {78},
  year         = {2018},
}