PT Journal
AU ATLAS Collaboration (Aaboud, Mea
   Alvarez Piqueras, D
   Barranco Navarro, L
   Cabrera Urban, S
   Castillo Gimenez, V
   Cerda Alberich, L
   Costa, MJ
   Escobar, C
   Estrada Pastor, O
   Fernandez Martinez, P
   Ferrer, A
   Fiorini, L
   Fuster, J
   Garcia, C
   Garcia Navarro, JE
   Gonzalez de la Hoz, S
   Higon-Rodriguez, E
   Jimenez Pena, J
   Lacasta, C
   Madaffari, D
   Mamuzic, J
   Marti-Garcia, S
   Melini, D
   Mitsou, VA
   Pedraza Lopez, S
   Rodriguez Bosca, S
   Rodriguez Rodriguez, D
   Romero Adam, E
   Salt, J
   Sanchez Martinez, V
   Soldevila, U
   Sanchez, J
   Valero, A
   Valls Ferrer, JA
   Vos, M
TI Measurement of tau polarisation in Z/gamma* -> tau tau decays in proton-proton collisions at root s=8 TeV with the ATLAS detector
SO European Physical Journal C
JI Eur. Phys. J. C
PY 2018
BP 163
EP 30pp
VL 78
IS 2
DI 10.1140/epjc/s10052-018-5619-1
LA English
AB This paper presents a measurement of the polarisation of tau leptons produced in Z/gamma* -> tau tau decays which is performed with a dataset of proton-proton collisions at root 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/gamma* -> tau tau decays are reconstructed from a hadronically decaying tau lepton with a single charged particle in the final state, accompanied by a tau lepton that decays leptonically. The tau polarisation is inferred from the relative fraction of energy carried by charged and neutral hadrons in the hadronic tau decays. The polarisation is measured in a fiducial region that corresponds to the kinematic region accessible to this analysis. The tau polarisation extracted over the full phase space within the Z/gamma* mass range of 66 < mZ/gamma* < 116GeVis found to be P-tau = -0.14 +/- 0.02(stat)+/- 0.04(syst). It is in agreement with the Standard Model prediction of Pt = -0.1517 +/- 0.0019, which is obtained from the ALP-GEN event generator interfaced with the PYTHIA 6 parton shower modelling and the TAUOLA tau decay library.
ER