Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at s=13 TeV

The ATLAS collaboration

doi:10.1016/j.physletb.2022.137379

Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at s=13 TeV

The ATLAS collaboration

Aix-Marseille Université
University of Oklahoma
University of Massachusetts
Azerbaijan National Academy of Sciences
National Institute for Nuclear Physics
University of Pavia
University of Göttingen
Royal Holloway University of London
University of Toronto
University of Copenhagen
University of Sussex
Tel Aviv University
Technion-Israel Institute of Technology
Argonne National Laboratory
CERN
Abdus Salam International Centre for Theoretical Physics
King's College London
City University of New York
The University of Tokyo
Johannes Gutenberg University Mainz
IN2P3/CNRS
AGH University of Krakow
Northern Illinois University
Ludwig Maximilian University of Munich
Bogazici University
Istanbul University
Fondazione Bruno Kessler
University of Geneva
Rutherford Appleton Laboratory
University of California at Santa Cruz
Université Clermont Auvergne
Radboud University Nijmegen
Alexandru Ioan Cuza University of Iaşi
Laboratório de Instrumentação e Física Experimental de Partículas
University of Granada
IFT-UAM/CSIC
Joint Institute for Nuclear Research
McGill University
CAS - Institute of High Energy Physics
University of Rome Tor Vergata
Kyoto University
Lund University
P.N. Lebedev Physical Institute of the Russian Academy of Sciences
University of Bologna
University of Victoria BC
Universidad Nacional de La Plata

Research output: Contribution to journal › Article › peer-review

20 Scopus citations

Abstract

This letter documents a search for flavour-changing neutral currents (FCNCs), which are strongly suppressed in the Standard Model, in events with a photon and a top quark with the ATLAS detector. The analysis uses data collected in pp collisions at s=13 TeV during Run 2 of the LHC, corresponding to an integrated luminosity of 139 fb⁻¹. Both FCNC top-quark production and decay are considered. The final state consists of a charged lepton, missing transverse momentum, a b-tagged jet, one high-momentum photon and possibly additional jets. A multiclass deep neural network is used to classify events either as signal in one of the two categories, FCNC production or decay, or as background. No significant excess of events over the background prediction is observed and 95% CL upper limits are placed on the strength of left- and right-handed FCNC interactions. The 95% CL bounds on the branching fractions for the FCNC top-quark decays, estimated (expected) from both top-quark production and decay, are B(t→uγ)<0.85(0.88_−0.25 ^+0.37)×10⁻⁵ and B(t→cγ)<4.2(3.40_−0.95 ^+1.35)×10⁻⁵ for a left-handed tqγ coupling, and B(t→uγ)<1.2(1.20_−0.33 ^+0.50)×10⁻⁵ and B(t→cγ)<4.5(3.70_−1.03 ^+1.47)×10⁻⁵ for a right-handed coupling.

Original language	English
Article number	137379
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	842
DOIs	https://doi.org/10.1016/j.physletb.2022.137379
State	Published - Jul 10 2023

Access to Document

10.1016/j.physletb.2022.137379

Cite this

@article{c8d5b813454748b2baf12a8072775d47,

title = "Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at s=13 TeV",

abstract = "This letter documents a search for flavour-changing neutral currents (FCNCs), which are strongly suppressed in the Standard Model, in events with a photon and a top quark with the ATLAS detector. The analysis uses data collected in pp collisions at s=13 TeV during Run 2 of the LHC, corresponding to an integrated luminosity of 139 fb−1. Both FCNC top-quark production and decay are considered. The final state consists of a charged lepton, missing transverse momentum, a b-tagged jet, one high-momentum photon and possibly additional jets. A multiclass deep neural network is used to classify events either as signal in one of the two categories, FCNC production or decay, or as background. No significant excess of events over the background prediction is observed and 95\% CL upper limits are placed on the strength of left- and right-handed FCNC interactions. The 95\% CL bounds on the branching fractions for the FCNC top-quark decays, estimated (expected) from both top-quark production and decay, are B(t→uγ)<0.85(0.88−0.25 +0.37)×10−5 and B(t→cγ)<4.2(3.40−0.95 +1.35)×10−5 for a left-handed tqγ coupling, and B(t→uγ)<1.2(1.20−0.33 +0.50)×10−5 and B(t→cγ)<4.5(3.70−1.03 +1.47)×10−5 for a right-handed coupling.",

author = "\{The ATLAS collaboration\} and G. Aad and B. Abbott and Abbott, \{D. C.\} and O. Abdinov and Abud, \{A. Abed\} and K. Abeling and Abhayasinghe, \{D. K.\} and Abidi, \{S. H.\} and AbouZeid, \{O. S.\} and Abraham, \{N. L.\} and H. Abramowicz and H. Abreu and Y. Abulaiti and Acharya, \{B. S.\} and B. Achkar and S. Adachi and L. Adam and Bourdarios, \{C. Adam\} and L. Adamczyk and L. Adamek and J. Adelman and M. Adersberger and A. Adiguzel and S. Adorni and T. Adye and Affolder, \{A. A.\} and Y. Afik and C. Agapopoulou and Agaras, \{M. N.\} and A. Aggarwal and C. Agheorghiesei and Aguilar-Saavedra, \{J. A.\} and F. Ahmadov and Ahmed, \{W. S.\} and X. Ai and G. Aielli and S. Akatsuka and {\AA}kesson, \{T. P.A.\} and E. Akilli and Akimov, \{A. V.\} and \{Al Khoury\}, K. and Alberghi, \{G. L.\} and J. Albert and Verzini, \{M. J.Alconada\} and S. Alderweireldt and H. Arnold and V. Dao and J. Hobbs and J. Jia and D. Tsybychev",

note = "Publisher Copyright: {\textcopyright} 2022 The Author(s)",

year = "2023",

month = jul,

day = "10",

doi = "10.1016/j.physletb.2022.137379",

language = "English",

volume = "842",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

}

TY - JOUR

T1 - Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at s=13 TeV

AU - The ATLAS collaboration

AU - Aad, G.

AU - Abbott, B.

AU - Abbott, D. C.

AU - Abdinov, O.

AU - Abud, A. Abed

AU - Abeling, K.

AU - Abhayasinghe, D. K.

AU - Abidi, S. H.

AU - AbouZeid, O. S.

AU - Abraham, N. L.

AU - Abramowicz, H.

AU - Abreu, H.

AU - Abulaiti, Y.

AU - Acharya, B. S.

AU - Achkar, B.

AU - Adachi, S.

AU - Adam, L.

AU - Bourdarios, C. Adam

AU - Adamczyk, L.

AU - Adamek, L.

AU - Adelman, J.

AU - Adersberger, M.

AU - Adiguzel, A.

AU - Adorni, S.

AU - Adye, T.

AU - Affolder, A. A.

AU - Afik, Y.

AU - Agapopoulou, C.

AU - Agaras, M. N.

AU - Aggarwal, A.

AU - Agheorghiesei, C.

AU - Aguilar-Saavedra, J. A.

AU - Ahmadov, F.

AU - Ahmed, W. S.

AU - Ai, X.

AU - Aielli, G.

AU - Akatsuka, S.

AU - Åkesson, T. P.A.

AU - Akilli, E.

AU - Akimov, A. V.

AU - Al Khoury, K.

AU - Alberghi, G. L.

AU - Albert, J.

AU - Verzini, M. J.Alconada

AU - Alderweireldt, S.

AU - Arnold, H.

AU - Dao, V.

AU - Hobbs, J.

AU - Jia, J.

AU - Tsybychev, D.

PY - 2023/7/10

Y1 - 2023/7/10

N2 - This letter documents a search for flavour-changing neutral currents (FCNCs), which are strongly suppressed in the Standard Model, in events with a photon and a top quark with the ATLAS detector. The analysis uses data collected in pp collisions at s=13 TeV during Run 2 of the LHC, corresponding to an integrated luminosity of 139 fb−1. Both FCNC top-quark production and decay are considered. The final state consists of a charged lepton, missing transverse momentum, a b-tagged jet, one high-momentum photon and possibly additional jets. A multiclass deep neural network is used to classify events either as signal in one of the two categories, FCNC production or decay, or as background. No significant excess of events over the background prediction is observed and 95% CL upper limits are placed on the strength of left- and right-handed FCNC interactions. The 95% CL bounds on the branching fractions for the FCNC top-quark decays, estimated (expected) from both top-quark production and decay, are B(t→uγ)<0.85(0.88−0.25 +0.37)×10−5 and B(t→cγ)<4.2(3.40−0.95 +1.35)×10−5 for a left-handed tqγ coupling, and B(t→uγ)<1.2(1.20−0.33 +0.50)×10−5 and B(t→cγ)<4.5(3.70−1.03 +1.47)×10−5 for a right-handed coupling.

AB - This letter documents a search for flavour-changing neutral currents (FCNCs), which are strongly suppressed in the Standard Model, in events with a photon and a top quark with the ATLAS detector. The analysis uses data collected in pp collisions at s=13 TeV during Run 2 of the LHC, corresponding to an integrated luminosity of 139 fb−1. Both FCNC top-quark production and decay are considered. The final state consists of a charged lepton, missing transverse momentum, a b-tagged jet, one high-momentum photon and possibly additional jets. A multiclass deep neural network is used to classify events either as signal in one of the two categories, FCNC production or decay, or as background. No significant excess of events over the background prediction is observed and 95% CL upper limits are placed on the strength of left- and right-handed FCNC interactions. The 95% CL bounds on the branching fractions for the FCNC top-quark decays, estimated (expected) from both top-quark production and decay, are B(t→uγ)<0.85(0.88−0.25 +0.37)×10−5 and B(t→cγ)<4.2(3.40−0.95 +1.35)×10−5 for a left-handed tqγ coupling, and B(t→uγ)<1.2(1.20−0.33 +0.50)×10−5 and B(t→cγ)<4.5(3.70−1.03 +1.47)×10−5 for a right-handed coupling.

UR - https://www.scopus.com/pages/publications/85146929561

U2 - 10.1016/j.physletb.2022.137379

DO - 10.1016/j.physletb.2022.137379

M3 - Article

AN - SCOPUS:85146929561

SN - 0370-2693

VL - 842

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

M1 - 137379

ER -

Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at s=13 TeV

Abstract

Access to Document

Other files and links

Fingerprint

Cite this