Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Search for flavour-changing neutral-current interactions of a top quark and a gluon in pp collisions at √s=13 TeV with the ATLAS detector

Aad, G. ; Åkesson, T.P.A. LU orcid ; Corrigan, E.E. LU ; Doglioni, C. LU ; Geisen, J. LU orcid ; Hansen, E. LU ; Hedberg, V. LU ; Jarlskog, G. LU ; Konya, B. LU and Lytken, E. LU orcid , et al. (2022) In European Physical Journal C 82(4).
Abstract
A search is presented for the production of a single top quark via left-handed flavour-changing neutral-current (FCNC) interactions of a top quark, a gluon and an up or charm quark. Two production processes are considered: u+ g→ t and c+ g→ t. The analysis is based on proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. The data set corresponds to an integrated luminosity of 139 fb- 1. Events with exactly one electron or muon, exactly one b-tagged jet and missing transverse momentum are selected, resembling the decay products of a singly produced top quark. Neural networks based on kinematic variables differentiate between events from the two signal processes and events from background... (More)
A search is presented for the production of a single top quark via left-handed flavour-changing neutral-current (FCNC) interactions of a top quark, a gluon and an up or charm quark. Two production processes are considered: u+ g→ t and c+ g→ t. The analysis is based on proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. The data set corresponds to an integrated luminosity of 139 fb- 1. Events with exactly one electron or muon, exactly one b-tagged jet and missing transverse momentum are selected, resembling the decay products of a singly produced top quark. Neural networks based on kinematic variables differentiate between events from the two signal processes and events from background processes. The measured data are consistent with the background-only hypothesis, and limits are set on the production cross-sections of the signal processes: σ(u+g→t)×B(t→Wb)×B(W→ℓν)<3.0pb and σ(c+g→t)×B(t→Wb)×B(W→ℓν)<4.7pb at the 95% confidence level, with B(W→ ℓν) = 0.325 being the sum of branching ratios of all three leptonic decay modes of the W boson. Based on the framework of an effective field theory, the cross-section limits are translated into limits on the strengths of the tug and tcg couplings occurring in the theory: |CuGut|/Λ2<0.057TeV- 2 and |CuGct|/Λ2<0.14TeV- 2. These bounds correspond to limits on the branching ratios of FCNC-induced top-quark decays: B(t→ u+ g) < 0.61 × 10 - 4 and B(t→ c+ g) < 3.7 × 10 - 4. © 2022, The Author(s). (Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; ; and , et al. (More)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; and (Less)
author collaboration
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
European Physical Journal C
volume
82
issue
4
article number
334
publisher
Springer
external identifiers
  • scopus:85128761210
ISSN
1434-6044
DOI
10.1140/epjc/s10052-022-10182-7
language
English
LU publication?
yes
id
c7e247be-f37d-40e7-9aba-e2f59c422fa2
date added to LUP
2022-09-12 10:20:11
date last changed
2023-04-05 22:58:11
@article{c7e247be-f37d-40e7-9aba-e2f59c422fa2,
  abstract     = {{A search is presented for the production of a single top quark via left-handed flavour-changing neutral-current (FCNC) interactions of a top quark, a gluon and an up or charm quark. Two production processes are considered: u+ g→ t and c+ g→ t. The analysis is based on proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. The data set corresponds to an integrated luminosity of 139 fb- 1. Events with exactly one electron or muon, exactly one b-tagged jet and missing transverse momentum are selected, resembling the decay products of a singly produced top quark. Neural networks based on kinematic variables differentiate between events from the two signal processes and events from background processes. The measured data are consistent with the background-only hypothesis, and limits are set on the production cross-sections of the signal processes: σ(u+g→t)×B(t→Wb)×B(W→ℓν)&lt;3.0pb and σ(c+g→t)×B(t→Wb)×B(W→ℓν)&lt;4.7pb at the 95% confidence level, with B(W→ ℓν) = 0.325 being the sum of branching ratios of all three leptonic decay modes of the W boson. Based on the framework of an effective field theory, the cross-section limits are translated into limits on the strengths of the tug and tcg couplings occurring in the theory: |CuGut|/Λ2&lt;0.057TeV- 2 and |CuGct|/Λ2&lt;0.14TeV- 2. These bounds correspond to limits on the branching ratios of FCNC-induced top-quark decays: B(t→ u+ g) &lt; 0.61 × 10 - 4 and B(t→ c+ g) &lt; 3.7 × 10 - 4. © 2022, The Author(s).}},
  author       = {{Aad, G. and Åkesson, T.P.A. and Corrigan, E.E. and Doglioni, C. and Geisen, J. and Hansen, E. and Hedberg, V. and Jarlskog, G. and Konya, B. and Lytken, E. and Mankinen, K.H. and Marcon, C. 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         = {{1434-6044}},
  language     = {{eng}},
  number       = {{4}},
  publisher    = {{Springer}},
  series       = {{European Physical Journal C}},
  title        = {{Search for flavour-changing neutral-current interactions of a top quark and a gluon in pp collisions at √s=13 TeV with the ATLAS detector}},
  url          = {{http://dx.doi.org/10.1140/epjc/s10052-022-10182-7}},
  doi          = {{10.1140/epjc/s10052-022-10182-7}},
  volume       = {{82}},
  year         = {{2022}},
}