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-.

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Abstract

This paper presents a measurement of the polarisation of τ leptons produced in Z / γ ∗ → τ τ 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 ∗ → τ τ 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 < m Z / γ ∗ < 116 GeV is found to be P τ = - 0.14 ± 0.02 ( stat ) ± 0.04 ( syst ) . It is in agreement with the Standard Model prediction of P τ = - 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: 25 Jan 2024 09:03
DOI: 10.1140/epjc/s10052-018-5619-1
Open Access URL: http://10.0.4.116/epjc/s10052-018-5619-1
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3019640