Measurement of the polarisation of W bosons produced in top-quark decays using dilepton events at √s=13 TeV with the ATLAS experiment

A measurement of the polarisation of W bosons produced in top-quark decays is presented, using proton-proton collision data at a centre-of-mass energy of √s=13 TeV. The data were collected by the ATLAS detector at the Large Hadron Collider and correspond to an integrated luminosity of 139 fb−1. The...

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Main Authors: Aad, Georges (Author) , Baltes, Lisa Marie (Author) , Bartels, Falk (Author) , Castillo, Florencia Luciana (Author) , Czurylo, Marta (Author) , Rio, Fernando del (Author) , Dittmeier, Sebastian (Author) , Dunford, Monica (Author) , Franchino, Silvia (Author) , Junkermann, Thomas (Author) , Klassen, Martin (Author) , Mkrtchyan, Tigran (Author) , Ott, Philipp (Author) , Rassloff, Damir Fabrice (Author) , Rodriguez Bosca, Sergi (Author) , Sauer, Christof (Author) , Schöning, André (Author) , Schultz-Coulon, Hans-Christian (Author) , Sothilingam, Varsiha (Author) , Stamen, Rainer (Author) , Starovoitov, Pavel (Author) , Vigani, Luigi (Author) , Weber, Sebastian (Author) , Wessels, Martin (Author) , Zinßer, Joachim (Author)
Corporate Author: ATLAS Collaboration (Author)
Format: Article (Journal)
Language:English
Published: 10 August 2023
In: Physics letters
Year: 2023, Volume: 843, Pages: 1-22
ISSN:1873-2445
DOI:10.1016/j.physletb.2023.137829
Online Access:Verlag, kostenfrei, Volltext: https://doi.org/10.1016/j.physletb.2023.137829
Verlag, kostenfrei, Volltext: https://www.sciencedirect.com/science/article/pii/S0370269323001636
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Author Notes:The ATLAS Collaboration
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Summary:A measurement of the polarisation of W bosons produced in top-quark decays is presented, using proton-proton collision data at a centre-of-mass energy of √s=13 TeV. The data were collected by the ATLAS detector at the Large Hadron Collider and correspond to an integrated luminosity of 139 fb−1. The measurement is performed selecting tt¯ events decaying into final states with two charged leptons (electrons or muons) and at least two b-tagged jets. The polarisation is extracted from the differential cross-section distribution of the cos⁡θ⁎ variable, where θ⁎ is the angle between the momentum direction of the charged lepton from the W boson decay and the reversed momentum direction of the b-quark from the top-quark decay, both calculated in the W boson rest frame. Parton-level results, corrected for the detector acceptance and resolution, are presented for the cos⁡θ⁎ angle. The measured fractions of longitudinal, left- and right-handed polarisation states are found to be f0=0.684±0.005(stat.)±0.014(syst.), fL=0.318±0.003(stat.)±0.008(syst.) and fR=−0.002±0.002(stat.)±0.014(syst.), in agreement with the Standard Model prediction.
Item Description:Im Titel steht der Buchstabe s unter dem Wurzelsymbol
The ATLAS Collaboration: G. Aad, L.M. Baltes, F. Bartels, F.L. Castillo, M.M. Czurylo, F. Del Rio, S.J. Dittmeier, M. Dunford, S. Franchino, T. Junkermann, M. Klassen, T. Mkrtchyan, P.S. Ott, D.F. Rassloff, S. Rodriguez Bosca, A. Schoening, H-C. Schultz-Coulon, V. Sothilingam, R. Stamen, P. Starovoitov, L. Vigani, S.M. Weber, M. Wessels, J. Zinsser [und viele weitere]
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Physical Description:Online Resource
ISSN:1873-2445
DOI:10.1016/j.physletb.2023.137829