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

ATLAS Collaboration

doi:10.1140/epjc/s10052-018-5619-1

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

ATLAS Collaboration

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

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 P_τ= - 0.14 ± 0.02 (stat) ± 0.04 (syst). It is in agreement with the Standard Model prediction of P_τ= - 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.

Original language	English
Article number	163
Journal	European Physical Journal C
Volume	78
Issue number	2
DOIs	https://doi.org/10.1140/epjc/s10052-018-5619-1
State	Published - 1 Feb 2018

Funding

Funders	Funder number
Not added	ST/N000447/1
AvH Foundation
Benoziyo Center, Israel
CEA-DRF/IRFU
COLCIEN-CIAS
Canada Council
Cantons of Bern and Geneva
DNSRC	IN2P3-CNRS
DST/NRF
EU-ESF
MES of Russia
MESTD
MIZŠ
MNE/IFA
MSMT
MSSR
Minerva, Israel
RGC
Région Auvergne
VSC CR
Wal-lenberg Foundation
National Science Foundation	1624739
National Science Foundation
U.S. Department of Energy
Ontario Innovation Trust
Canarie
H2020 Marie Skłodowska-Curie Actions
Biomedical Research Foundation
Seventh Framework Programme	246806
Seventh Framework Programme
Arizona-Nevada Academy of Science
CERN
Compute Canada
National Research Council
College of Arts and Sciences, University of Nebraska-Lincoln
Glycemic Index Foundation
Natural Sciences and Engineering Research Council of Canada
Science and Technology Facilities Council	PP/E000452/1, ST/H001158/1, 1653101, ST/N000331/1, ST/H001158/2, GRIDPP, ST/N000277/1, 1668509
Science and Technology Facilities Council
Leverhulme Trust
Royal Society
British Skin Foundation
European Commission
Australian Research Council
Rozetta Institute
Singapore Eye Research Institute
Helmholtz-Gemeinschaft
Deutsche Forschungsgemeinschaft
Agence Nationale de la Recherche
Japan Society for the Promotion of Science
Ministry of Education, Culture, Sports, Science and Technology
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
Danmarks Grundforskningsfond
Canada Foundation for Innovation
Fundação de Amparo à Pesquisa do Estado de São Paulo
National Natural Science Foundation of China
Fundação para a Ciência e a Tecnologia
Bundesministerium für Bildung und Forschung
Austrian Science Fund
Agencia Nacional de Investigación y Desarrollo
Agencia Nacional de Promoción Científica y Tecnológica
Fonds Québécois de la Recherche sur la Nature et les Technologies
Ministerstvo Zdravotnictví Ceské Republiky
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
Ministerio de Economía y Competitividad
Bundesministerium für Wissenschaft, Forschung und Wirtschaft
General Secretariat for Research and Technology
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Ministry of Science and Technology
Joint Institute for Nuclear Research
Israel Science Foundation
Instituto Nazionale di Fisica Nucleare
Narodowe Centrum Nauki
Javna Agencija za Raziskovalno Dejavnost RS
Ministerstwo Nauki i Szkolnictwa Wyższego
Shota Rustaveli National Science Foundation
Israeli Centers for Research Excellence
Centre National pour la Recherche Scientifique et Technique
Horizon 2020
British Columbia Knowledge Development Fund
European Regional Development Fund
Institut Nacional d'Educacio Fisica de Catalunya, Generalitat de Catalunya
Fondation Partager le Savoir
National Research Center "Kurchatov Institute"
Ministry of Health of the Russian Federation

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10.1140/epjc/s10052-018-5619-1

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@article{93081974a12c4a5488c457994a5058c9,

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

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 τ= - 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.",

author = "{ATLAS Collaboration} and M. Aaboud and G. Aad and B. Abbott and O. Abdinov and B. Abeloos and Abidi, {S. H.} and AbouZeid, {O. S.} and Abraham, {N. L.} and H. Abramowicz and H. Abreu and R. Abreu and Y. Abulaiti and Acharya, {B. S.} and S. Adachi and L. Adamczyk and J. Adelman and M. Adersberger and T. Adye and Affolder, {A. A.} and Y. Afik and T. Agatonovic-Jovin and C. Agheorghiesei and Aguilar-Saavedra, {J. A.} and Ahlen, {S. P.} and F. Ahmadov and G. Aielli and S. Akatsuka and H. Akerstedt and {\AA}kesson, {T. P.A.} and E. Akilli and Akimov, {A. V.} and Alberghi, {G. L.} and J. Albert and P. Albicocco and {Alconada Verzini}, {M. J.} and Alderweireldt, {S. C.} and M. Aleksa and Aleksandrov, {I. N.} and G. Alexander and A. Ashkenazi and L. Barak and G. Bella and Y. Benhammou and T. Cao and E. Etzion and O. Kuprash and Lutz, {M. S.} and Y. Oren and M. Pitt and A. Soffer",

note = "Publisher Copyright: {\textcopyright} 2018, CERN for the benefit of the ATLAS collaboration.",

year = "2018",

month = feb,

day = "1",

doi = "10.1140/epjc/s10052-018-5619-1",

language = "אנגלית",

volume = "78",

journal = "European Physical Journal C",

issn = "1434-6044",

publisher = "Springer New York",

number = "2",

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TY - JOUR

T1 - Measurement of τ polarisation in Z/ γ∗→ ττ decays in proton–proton collisions at √s=8 TeV with the ATLAS detector

AU - ATLAS Collaboration

AU - Aaboud, M.

AU - Aad, G.

AU - Abbott, B.

AU - Abdinov, O.

AU - Abeloos, B.

AU - Abidi, S. H.

AU - AbouZeid, O. S.

AU - Abraham, N. L.

AU - Abramowicz, H.

AU - Abreu, H.

AU - Abreu, R.

AU - Abulaiti, Y.

AU - Acharya, B. S.

AU - Adachi, S.

AU - Adamczyk, L.

AU - Adelman, J.

AU - Adersberger, M.

AU - Adye, T.

AU - Affolder, A. A.

AU - Afik, Y.

AU - Agatonovic-Jovin, T.

AU - Agheorghiesei, C.

AU - Aguilar-Saavedra, J. A.

AU - Ahlen, S. P.

AU - Ahmadov, F.

AU - Aielli, G.

AU - Akatsuka, S.

AU - Akerstedt, H.

AU - Åkesson, T. P.A.

AU - Akilli, E.

AU - Akimov, A. V.

AU - Alberghi, G. L.

AU - Albert, J.

AU - Albicocco, P.

AU - Alconada Verzini, M. J.

AU - Alderweireldt, S. C.

AU - Aleksa, M.

AU - Aleksandrov, I. N.

AU - Alexander, G.

AU - Ashkenazi, A.

AU - Barak, L.

AU - Bella, G.

AU - Benhammou, Y.

AU - Cao, T.

AU - Etzion, E.

AU - Kuprash, O.

AU - Lutz, M. S.

AU - Oren, Y.

AU - Pitt, M.

AU - Soffer, A.

PY - 2018/2/1

Y1 - 2018/2/1

N2 - 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 τ= - 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.

AB - 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 τ= - 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.

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SN - 1434-6044

VL - 78

JO - European Physical Journal C

JF - European Physical Journal C

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M1 - 163

ER -

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

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