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

Aad, G. ; Åkesson, T.P.A. LU orcid ; Corrigan, E.E. LU ; Doglioni, C. LU ; Ekman, P.A. LU ; Geisen, J. LU orcid ; Hedberg, V. LU ; Herde, H. LU orcid ; Jarlskog, G. LU and Konya, B. LU , et al. (2023) In Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 843.
Abstract
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... (More)
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. © 2023 The Author(s) (Less)
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type
Contribution to journal
publication status
published
subject
in
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
volume
843
article number
137829
publisher
Elsevier
external identifiers
  • scopus:85165885818
ISSN
0370-2693
DOI
10.1016/j.physletb.2023.137829
language
English
LU publication?
yes
id
883058ad-3702-4be5-a0dd-717e5e0d0890
date added to LUP
2023-12-20 15:02:11
date last changed
2023-12-20 15:03:03
@article{883058ad-3702-4be5-a0dd-717e5e0d0890,
  abstract     = {{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. © 2023 The Author(s)}},
  author       = {{Aad, G. and Åkesson, T.P.A. and Corrigan, E.E. and Doglioni, C. and Ekman, P.A. and Geisen, J. and Hedberg, V. and Herde, H. and Jarlskog, G. and Konya, B. and Lytken, E. and Mjörnmark, J.U. and Poettgen, R. and Simpson, N.D. and Skorda, E. and Smirnova, O. and Zwalinski, L.}},
  issn         = {{0370-2693}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}},
  title        = {{Measurement of the polarisation of W bosons produced in top-quark decays using dilepton events at s=13 TeV with the ATLAS experiment}},
  url          = {{http://dx.doi.org/10.1016/j.physletb.2023.137829}},
  doi          = {{10.1016/j.physletb.2023.137829}},
  volume       = {{843}},
  year         = {{2023}},
}