his 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

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

Dondero P.;Farina E. M.;Fraternali M.;Introzzi G.;Livan M.;Negri A.;