Measurement of tau polarisation in Z/gamma* -> tau tau decays in proton-proton collisions at root s=8 TeV with the ATLAS detector



Aaboudd, M, Aad, G, Abbott, B, Abdinov, O, Abeloos, B, Abidi, SH, AbouZeid, OS, Abraham, NL, Abrainowicz, H, Abreu, H
et al (show 2886 more authors) (2018) Measurement of tau polarisation in Z/gamma* -> tau tau decays in proton-proton collisions at root s=8 TeV with the ATLAS detector EUROPEAN PHYSICAL JOURNAL C, 78 (2). 163-. ISSN 1434-6044, 1434-6052

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Abstract

This paper presents a measurement of the polarisation of τ leptons produced in Z/ γ<sup>∗</sup>→ 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<sup>- 1</sup> recorded with the ATLAS detector at the LHC in 2012. The Z/ γ<sup>∗</sup>→ 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<sup>∗</sup> mass range of 66 <mZ/ 116 GeV is found to be P<inf>τ</inf>= - 0.14 ± 0.02 (stat) ± 0.04 (syst). It is in agreement with the Standard Model prediction of P<inf>τ</inf>= - 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.

Item Type: Article
Additional Information: 44 pages in total, author list starting page 28, 6 figures, 7 tables, submitted to EPJC. Al l figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2015-18
Uncontrolled Keywords: ATLAS Collaboration
Depositing User: Symplectic Admin
Date Deposited: 10 Apr 2018 09:30
Last Modified: 22 Jan 2026 07:48
DOI: 10.1140/epjc/s10052-018-5619-1
Open Access URL: https://doi.org/10.1140/epjc/s10052-018-5619-1
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3019640
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