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Search for flavour-changing neutral current interactions of the top quark and the Higgs boson in events with a pair of τ-leptons 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 ; 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(6).
Abstract
A search for flavour-changing neutral current (FCNC) tqH interactions involving a top quark, another up-type quark (q = u, c), and a Standard Model (SM) Higgs boson decaying into a τ-lepton pair (H → τ + τ −) is presented. The search is based on a dataset of pp collisions at s = 13 TeV that corresponds to an integrated luminosity of 139 fb −1 recorded with the ATLAS detector at the Large Hadron Collider. Two processes are considered: single top quark FCNC production in association with a Higgs boson (pp → tH), and top quark pair production in which one of top quarks decays into Wb and the other decays into qH through the FCNC interactions. The search selects events with two hadronically decaying τ-lepton candidates (τ had) or at least one... (More)
A search for flavour-changing neutral current (FCNC) tqH interactions involving a top quark, another up-type quark (q = u, c), and a Standard Model (SM) Higgs boson decaying into a τ-lepton pair (H → τ + τ −) is presented. The search is based on a dataset of pp collisions at s = 13 TeV that corresponds to an integrated luminosity of 139 fb −1 recorded with the ATLAS detector at the Large Hadron Collider. Two processes are considered: single top quark FCNC production in association with a Higgs boson (pp → tH), and top quark pair production in which one of top quarks decays into Wb and the other decays into qH through the FCNC interactions. The search selects events with two hadronically decaying τ-lepton candidates (τ had) or at least one τ had with an additional lepton (e, μ), as well as multiple jets. Event kinematics is used to separate signal from the background through a multivariate discriminant. A slight excess of data is observed with a significance of 2.3σ above the expected SM background, and 95% CL upper limits on the t → qH branching ratios are derived. The observed (expected) 95% CL upper limits set on the t → cH and t → uH branching ratios are 9.4×10−4(4.8−1.4+2.2×10−4) and 6.9×10−4(3.5−1.0+1.5×10−4) , respectively. The corresponding combined observed (expected) upper limits on the dimension-6 operator Wilson coefficients in the effective tqH couplings are Ccϕ < 1.35 (0.97) and Cuϕ < 1.16 (0.82). [Figure not available: see fulltext.] © 2023, The Author(s). (Less)
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publishing date
type
Contribution to journal
publication status
published
subject
keywords
Flavour Changing Neutral Currents, Hadron-Hadron Scattering, Higgs Physics, Top Physics
in
Journal of High Energy Physics
volume
2023
issue
6
article number
155
publisher
Springer
external identifiers
  • scopus:85163658273
ISSN
1029-8479
DOI
10.1007/JHEP06(2023)155
language
English
LU publication?
yes
id
be084173-5e2f-46ba-8496-60bc66fd5e5e
date added to LUP
2023-11-20 16:11:15
date last changed
2023-11-20 16:14:58
@article{be084173-5e2f-46ba-8496-60bc66fd5e5e,
  abstract     = {{A search for flavour-changing neutral current (FCNC) tqH interactions involving a top quark, another up-type quark (q = u, c), and a Standard Model (SM) Higgs boson decaying into a τ-lepton pair (H → τ + τ  −) is presented. The search is based on a dataset of pp collisions at s = 13 TeV that corresponds to an integrated luminosity of 139 fb −1 recorded with the ATLAS detector at the Large Hadron Collider. Two processes are considered: single top quark FCNC production in association with a Higgs boson (pp → tH), and top quark pair production in which one of top quarks decays into Wb and the other decays into qH through the FCNC interactions. The search selects events with two hadronically decaying τ-lepton candidates (τ had) or at least one τ had with an additional lepton (e, μ), as well as multiple jets. Event kinematics is used to separate signal from the background through a multivariate discriminant. A slight excess of data is observed with a significance of 2.3σ above the expected SM background, and 95% CL upper limits on the t → qH branching ratios are derived. The observed (expected) 95% CL upper limits set on the t → cH and t → uH branching ratios are 9.4×10−4(4.8−1.4+2.2×10−4) and 6.9×10−4(3.5−1.0+1.5×10−4) , respectively. The corresponding combined observed (expected) upper limits on the dimension-6 operator Wilson coefficients in the effective tqH couplings are Ccϕ &lt; 1.35 (0.97) and Cuϕ &lt; 1.16 (0.82). [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 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         = {{1029-8479}},
  keywords     = {{Flavour Changing Neutral Currents; Hadron-Hadron Scattering; Higgs Physics; Top Physics}},
  language     = {{eng}},
  number       = {{6}},
  publisher    = {{Springer}},
  series       = {{Journal of High Energy Physics}},
  title        = {{Search for flavour-changing neutral current interactions of the top quark and the Higgs boson in events with a pair of τ-leptons in pp collisions at √s = 13 TeV with the ATLAS detector}},
  url          = {{http://dx.doi.org/10.1007/JHEP06(2023)155}},
  doi          = {{10.1007/JHEP06(2023)155}},
  volume       = {{2023}},
  year         = {{2023}},
}