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Search for a new scalar resonance in flavour-changing neutral-current top-quark decays t → qX (q = u, c), with X → bb¯ , in proton-proton collisions at √s = 13 TeV with the ATLAS detector

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 ; Jarlskog, G. LU ; Konya, B. LU and Lytken, E. LU orcid , et al. (2023) In Journal of High Energy Physics 2023(7).
Abstract
A search for flavour-changing neutral-current decays of a top quark into an up-type quark (either up or charm) and a light scalar particle X decaying into a bottom anti-bottom quark pair is presented. The search focuses on top-quark pair production where one top quark decays to qX, with X → bb¯ , and the other top quark decays according to the Standard Model, with the W boson decaying leptonically. The final state is thus characterised by an isolated electron or muon and at least four jets. Events are categorised according to the multiplicity of jets and jets tagged as originating from b-quarks, and a neural network is used to discriminate between signal and background processes. The data analysed correspond to 139 fb −1 of proton–proton... (More)
A search for flavour-changing neutral-current decays of a top quark into an up-type quark (either up or charm) and a light scalar particle X decaying into a bottom anti-bottom quark pair is presented. The search focuses on top-quark pair production where one top quark decays to qX, with X → bb¯ , and the other top quark decays according to the Standard Model, with the W boson decaying leptonically. The final state is thus characterised by an isolated electron or muon and at least four jets. Events are categorised according to the multiplicity of jets and jets tagged as originating from b-quarks, and a neural network is used to discriminate between signal and background processes. The data analysed correspond to 139 fb −1 of proton–proton collisions at a centre-of-mass energy of 13 TeV, recorded with the ATLAS detector at the LHC. The 95% confidence-level upper limits between 0.019% and 0.062% are derived for the branching fraction B (t → uX) and between 0.018% and 0.078% for the branching fraction B (t → cX), for masses of the scalar particle X between 20 and 160 GeV. [Figure not available: see fulltext.] © 2023, The Author(s). (Less)
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author collaboration
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publishing date
type
Contribution to journal
publication status
published
subject
keywords
Hadron-Hadron Scattering
in
Journal of High Energy Physics
volume
2023
issue
7
article number
199
publisher
Springer
external identifiers
  • scopus:85174264679
ISSN
1029-8479
DOI
10.1007/JHEP07(2023)199
language
English
LU publication?
yes
id
335719db-05a6-4463-86c4-84fd7477442e
date added to LUP
2024-01-16 11:30:30
date last changed
2024-01-16 11:33:03
@article{335719db-05a6-4463-86c4-84fd7477442e,
  abstract     = {{A search for flavour-changing neutral-current decays of a top quark into an up-type quark (either up or charm) and a light scalar particle X decaying into a bottom anti-bottom quark pair is presented. The search focuses on top-quark pair production where one top quark decays to qX, with X → bb¯ , and the other top quark decays according to the Standard Model, with the W boson decaying leptonically. The final state is thus characterised by an isolated electron or muon and at least four jets. Events are categorised according to the multiplicity of jets and jets tagged as originating from b-quarks, and a neural network is used to discriminate between signal and background processes. The data analysed correspond to 139 fb −1 of proton–proton collisions at a centre-of-mass energy of 13 TeV, recorded with the ATLAS detector at the LHC. The 95% confidence-level upper limits between 0.019% and 0.062% are derived for the branching fraction B (t → uX) and between 0.018% and 0.078% for the branching fraction B (t → cX), for masses of the scalar particle X between 20 and 160 GeV. [Figure not available: see fulltext.] © 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 Jarlskog, G. and Konya, B. and Lytken, E. and Mjörnmark, J.U. and Mullier, G.A. and Poettgen, R. and Simpson, N.D. and Skorda, E. and Smirnova, O. and Zwalinski, L.}},
  issn         = {{1029-8479}},
  keywords     = {{Hadron-Hadron Scattering}},
  language     = {{eng}},
  number       = {{7}},
  publisher    = {{Springer}},
  series       = {{Journal of High Energy Physics}},
  title        = {{Search for a new scalar resonance in flavour-changing neutral-current top-quark decays t → qX (q = u, c), with X → bb¯ , in proton-proton collisions at √s = 13 TeV with the ATLAS detector}},
  url          = {{http://dx.doi.org/10.1007/JHEP07(2023)199}},
  doi          = {{10.1007/JHEP07(2023)199}},
  volume       = {{2023}},
  year         = {{2023}},
}