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