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

Rimoldi, Marco; Mullier, Geoffrey; Miucci, Antonio; Merlassino, Claudia; Haug, Sigve; Weber, Michael; Meloni, Federico; Beck, Hans Peter; Ereditato, Antonio (2018). Measurement of τ polarisation in ℤ/γ *→ ττ decays in proton–proton collisions at √s = 8 TeV with the ATLAS detector. European physical journal. C - particles and fields, 78(2) EDP Sciences 10.1140/epjc/s10052-018-5619-1

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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/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 event generator interfaced with the PYTHIA 6 parton shower modelling and the TAUOLA τ decay library.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Laboratory for High Energy Physics (LHEP)

UniBE Contributor:

Haug, Sigve; Weber, Michael and Beck, Hans Peter

Subjects:

500 Science > 530 Physics

ISSN:

1434-6044

Publisher:

EDP Sciences

Language:

English

Submitter:

BORIS Import LHEP

Date Deposited:

27 Jun 2019 16:32

Last Modified:

02 Sep 2020 21:48

Publisher DOI:

10.1140/epjc/s10052-018-5619-1

Additional Information:

Kollaboration - Es sind nur die Berner Autoren namentlich erwaehnt

BORIS DOI:

10.7892/boris.129113

URI:

https://boris.unibe.ch/id/eprint/129113

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