Typ
CONF-Note
Gebiet
ATLAS
Autor
Aaboud, …, Lara Schildgen, Peter Wagner, Philip Bechtle, Klaus Desch et al. (für die ATLAS Collaboration-Kollaboration)
Titel
Measurement of Tau Polarisation in Z -> tautau Decays in Proton-Proton Collisions at sqrt(s) = 8 TeV with the ATLAS Detector
Datum
2017-07
Reportnummer
ATLAS-CONF-2017-049
Kurzfassung
This note 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 (τ→hadrons + ν) with a single charged particle in the final state accompanied by a τ lepton that decays leptonically (τ→e/μ + νν¯). 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 in the full phase space in the Z/γ∗ mass range of 66 GeV <mZ/γ∗< 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 generator interfaced with Pythia6 and Tauola.
Link
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/CONFNOTES/ATLAS-CONF-2017-049/