Title
Measurement of τ polarisation in Z/ γ∗→ ττ decays in proton–proton collisions at √s=8 TeV with the ATLAS detector
Date Issued
01 February 2018
Access level
open access
Resource Type
journal article
Author(s)
Aaboud M.
Aad G.
Abbott B.
Abdinov O.
Abeloos B.
Abidi S.H.
AbouZeid O.S.
Abraham N.L.
Abramowicz H.
Abreu H.
Abreu R.
Abulaiti Y.
Acharya B.S.
Adachi S.
Adamczyk L.
Adelman J.
Adersberger M.
Adye T.
Affolder A.A.
Afik Y.
Agatonovic-Jovin T.
Agheorghiesei C.
Aguilar-Saavedra J.A.
Ahlen S.P.
Ahmadov F.
Aielli G.
Akatsuka S.
Akerstedt H.
Åkesson T.P.A.
Akilli E.
Akimov A.V.
Alberghi G.L.
Albert J.
Albicocco P.
Alconada Verzini M.J.
Alderweireldt S.C.
Aleksa M.
Aleksandrov I.N.
Alexa C.
Alexander G.
Alexopoulos T.
Alhroob M.
Ali B.
Aliev M.
Alimonti G.
Alison J.
Alkire S.P.
Allbrooke B.M.M.
Allen B.W.
Allport P.P.
Aloisio A.
Alonso A.
Alonso F.
Alpigiani C.
Alshehri A.A.
Alstaty M.I.
Alvarez Gonzalez B.
Álvarez Piqueras D.
Alviggi M.G.
Amadio B.T.
Amaral Coutinho Y.
Amelung C.
Amidei D.
Amor Dos Santos S.P.
Amoroso S.
Amundsen G.
Anastopoulos C.
Ancu L.S.
Andari N.
Andeen T.
Anders C.F.
Anders J.K.
Anderson K.J.
Andreazza A.
Andrei V.
Angelidakis S.
Angelozzi I.
Angerami A.
Anisenkov A.V.
Anjos N.
Annovi A.
Antel C.
Antonelli M.
Antonov A.
Antrim D.J.
Anulli F.
Aoki M.
Aperio Bella L.
Arabidze G.
Arai Y.
Araque J.P.
Araujo Ferraz V.
Arce A.T.H.
Ardell R.E.
Arduh F.A.
Arguin J.F.
Argyropoulos S.
Arik M.
Armbruster A.J.
Armitage L.J.
Publisher(s)
Springer New York LLC
Abstract
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.
Volume
78
Issue
2
Language
English
OCDE Knowledge area
Física de partículas, Campos de la Física
Física atómica, molecular y química
Scopus EID
2-s2.0-85042560791
Source
European Physical Journal C
ISSN of the container
14346044
Sponsor(s)
Acknowledgements We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIEN-CIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS, CEA-DRF/IRFU, France; SRNSF, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; NWO, Netherlands; RCN, Norway; MNiSW and NCN, Poland; FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZŠ, Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wal-lenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TAEK, Turkey; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, the Canada Council, CANARIE, CRC, Compute Canada, FQRNT, and the Ontario Innovation Trust, Canada; EPLANET, ERC, ERDF, FP7, Horizon 2020 and Marie Skłodowska-Curie Actions, European Union; Investissements d’Avenir Labex and Idex, ANR, Région Auvergne and Fondation Partager le Savoir, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF; BSF, GIF and Minerva, Israel; BRF, Norway; CERCA Programme Generalitat de Catalunya, Generalitat Valen-ciana, Spain; the Royal Society and Leverhulme Trust, United Kingdom. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN, the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (UK) and BNL (USA), the Tier-2 facilities worldwide and large non-WLCG resource providers. Major contributors of computing resources are listed in Ref. [51].
Sources of information:
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Scopus