Search for FCNC single top-quark production at √s=7 TeV with the ATLAS detector

ATLAS Collaboration

doi:10.1016/j.physletb.2012.05.022

Search for FCNC single top-quark production at √s=7 TeV with the ATLAS detector

ATLAS Collaboration

Kutahya Dumlupinar University
Istanbul Technical University
West University of Timisoara
University of Applied Sciences Wiener Neustadt
University of Freiburg
University of Oklahoma
Institute for High Energy Physics
University of Geneva
University of Oxford
Azerbaijan National Academy of Sciences
Oklahoma State University
Michigan State University
University of Toronto
Tel Aviv University
Université Paris-Sud
National Institute for Nuclear Physics
University of Milan
Abdus Salam International Centre for Theoretical Physics
AGH University of Krakow
United States Department of Energy
Hampton University
Yale University
Max Planck Institute for Physics (Werner Heisenberg Institute)
Ludwig Maximilian University of Munich
Queen Mary University of London
Rutherford Appleton Laboratory
Brandeis University
University of Granada
Laboratório de Instrumentação e Física Experimental de Partículas
Johannes Gutenberg University Mainz
Boston University
Stony Brook University
University of Texas at Dallas
University of Rome Tor Vergata
Bogazici University
Lund University
The University of Tokyo
RAS - P.N. Lebedev Physics Institute
Kobe University
SUNY Albany
Royal Holloway University of London
University of Victoria BC
Laboratoire de Physique Subatomique et de Cosmologie de Grenoble
CERN
Joint Institute for Nuclear Research
Horia Hulubei National Institute of Physics and Nuclear Engineering
National Technical University of Athens
University of Bonn
Humboldt University of Berlin
University of Pennsylvania
University of Glasgow

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

66 Citations (Scopus)

Abstract

A search for the production of single top-quarks via flavour-changing neutral-currents is presented. Data collected with the ATLAS detector at a centre-of-mass energy of s=7 TeV, corresponding to an integrated luminosity of 2.05 fb⁻¹, are used. Candidate events with a semileptonic top-quark decay signature are classified as signal- or background-like events by using several kinematic variables as input to a neural network. No signal is observed in the neural network output distribution and a Bayesian upper limit is placed on the production cross-section. The observed upper limit at 95% confidence level on the cross-section multiplied by the t→Wb branching fraction is measured to be σ_qg→t×B(t→Wb)<3.9 pb. This upper limit is converted using a model-independent approach into upper limits on the coupling strengths κ_ugt/Λ<6.9⋅10⁻³ TeV⁻¹ and κ_cgt/Λ<1.6⋅10⁻² TeV⁻¹, where Λ is the new physics scale, and on the branching fractions B(t→ug)<5.7⋅10⁻⁵ and B(t→cg)<2.7⋅10⁻⁴.

Original language	English
Pages (from-to)	351-369
Number of pages	19
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	712
Issue number	4-5
DOIs	https://doi.org/10.1016/j.physletb.2012.05.022
Publication status	Published - 12 Jun 2012
Externally published	Yes

Keywords

FCNC
Heavy-quark production
Single top quark
Top physics

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10.1016/j.physletb.2012.05.022

Cite this

@article{5ba8d98d5b624e0e87486258ea6964ef,

title = "Search for FCNC single top-quark production at √s=7 TeV with the ATLAS detector",

abstract = "A search for the production of single top-quarks via flavour-changing neutral-currents is presented. Data collected with the ATLAS detector at a centre-of-mass energy of s=7 TeV, corresponding to an integrated luminosity of 2.05 fb−1, are used. Candidate events with a semileptonic top-quark decay signature are classified as signal- or background-like events by using several kinematic variables as input to a neural network. No signal is observed in the neural network output distribution and a Bayesian upper limit is placed on the production cross-section. The observed upper limit at 95\% confidence level on the cross-section multiplied by the t→Wb branching fraction is measured to be σqg→t×B(t→Wb)<3.9 pb. This upper limit is converted using a model-independent approach into upper limits on the coupling strengths κugt/Λ<6.9⋅10−3 TeV−1 and κcgt/Λ<1.6⋅10−2 TeV−1, where Λ is the new physics scale, and on the branching fractions B(t→ug)<5.7⋅10−5 and B(t→cg)<2.7⋅10−4.",

keywords = "FCNC, Heavy-quark production, Single top quark, Top physics",

author = "\{ATLAS Collaboration\} and G. Aad and B. Abbott and J. Abdallah and Abdelalim, \{A. A.\} and A. Abdesselam and O. Abdinov and B. Abi and M. Abolins and AbouZeid, \{O. S.\} and H. Abramowicz and H. Abreu and E. Acerbi and Acharya, \{B. S.\} and L. Adamczyk and Adams, \{D. L.\} and Addy, \{T. N.\} and J. Adelman and M. Aderholz and S. Adomeit and P. Adragna and T. Adye and S. Aefsky and Aguilar-Saavedra, \{J. A.\} and M. Aharrouche and Ahlen, \{S. P.\} and F. Ahles and A. Ahmad and M. Ahsan and G. Aielli and T. Akdogan and {\AA}kesson, \{T. P.A.\} and G. Akimoto and Akimov, \{A. V.\} and A. Akiyama and Alam, \{M. S.\} and Alam, \{M. A.\} and J. Albert and S. Albrand and M. Aleksa and Aleksandrov, \{I. N.\} and F. Alessandria and C. Alexa and G. Alexander and G. Alexandre and T. Alexopoulos and M. Alhroob and M. Aliev and G. Alimonti and J. Alison and A. Moraes",

note = "Publisher Copyright: {\textcopyright} 2012 CERN",

year = "2012",

month = jun,

day = "12",

doi = "10.1016/j.physletb.2012.05.022",

language = "English",

volume = "712",

pages = "351--369",

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

issn = "0370-2693",

number = "4-5",

}

TY - JOUR

T1 - Search for FCNC single top-quark production at √s=7 TeV with the ATLAS detector

AU - ATLAS Collaboration

AU - Aad, G.

AU - Abbott, B.

AU - Abdallah, J.

AU - Abdelalim, A. A.

AU - Abdesselam, A.

AU - Abdinov, O.

AU - Abi, B.

AU - Abolins, M.

AU - AbouZeid, O. S.

AU - Abramowicz, H.

AU - Abreu, H.

AU - Acerbi, E.

AU - Acharya, B. S.

AU - Adamczyk, L.

AU - Adams, D. L.

AU - Addy, T. N.

AU - Adelman, J.

AU - Aderholz, M.

AU - Adomeit, S.

AU - Adragna, P.

AU - Adye, T.

AU - Aefsky, S.

AU - Aguilar-Saavedra, J. A.

AU - Aharrouche, M.

AU - Ahlen, S. P.

AU - Ahles, F.

AU - Ahmad, A.

AU - Ahsan, M.

AU - Aielli, G.

AU - Akdogan, T.

AU - Åkesson, T. P.A.

AU - Akimoto, G.

AU - Akimov, A. V.

AU - Akiyama, A.

AU - Alam, M. S.

AU - Alam, M. A.

AU - Albert, J.

AU - Albrand, S.

AU - Aleksa, M.

AU - Aleksandrov, I. N.

AU - Alessandria, F.

AU - Alexa, C.

AU - Alexander, G.

AU - Alexandre, G.

AU - Alexopoulos, T.

AU - Alhroob, M.

AU - Aliev, M.

AU - Alimonti, G.

AU - Alison, J.

AU - Moraes, A.

PY - 2012/6/12

Y1 - 2012/6/12

N2 - A search for the production of single top-quarks via flavour-changing neutral-currents is presented. Data collected with the ATLAS detector at a centre-of-mass energy of s=7 TeV, corresponding to an integrated luminosity of 2.05 fb−1, are used. Candidate events with a semileptonic top-quark decay signature are classified as signal- or background-like events by using several kinematic variables as input to a neural network. No signal is observed in the neural network output distribution and a Bayesian upper limit is placed on the production cross-section. The observed upper limit at 95% confidence level on the cross-section multiplied by the t→Wb branching fraction is measured to be σqg→t×B(t→Wb)<3.9 pb. This upper limit is converted using a model-independent approach into upper limits on the coupling strengths κugt/Λ<6.9⋅10−3 TeV−1 and κcgt/Λ<1.6⋅10−2 TeV−1, where Λ is the new physics scale, and on the branching fractions B(t→ug)<5.7⋅10−5 and B(t→cg)<2.7⋅10−4.

AB - A search for the production of single top-quarks via flavour-changing neutral-currents is presented. Data collected with the ATLAS detector at a centre-of-mass energy of s=7 TeV, corresponding to an integrated luminosity of 2.05 fb−1, are used. Candidate events with a semileptonic top-quark decay signature are classified as signal- or background-like events by using several kinematic variables as input to a neural network. No signal is observed in the neural network output distribution and a Bayesian upper limit is placed on the production cross-section. The observed upper limit at 95% confidence level on the cross-section multiplied by the t→Wb branching fraction is measured to be σqg→t×B(t→Wb)<3.9 pb. This upper limit is converted using a model-independent approach into upper limits on the coupling strengths κugt/Λ<6.9⋅10−3 TeV−1 and κcgt/Λ<1.6⋅10−2 TeV−1, where Λ is the new physics scale, and on the branching fractions B(t→ug)<5.7⋅10−5 and B(t→cg)<2.7⋅10−4.

KW - FCNC

KW - Heavy-quark production

KW - Single top quark

KW - Top physics

UR - https://www.scopus.com/pages/publications/85041997804

U2 - 10.1016/j.physletb.2012.05.022

DO - 10.1016/j.physletb.2012.05.022

M3 - Article

AN - SCOPUS:85041997804

SN - 0370-2693

VL - 712

SP - 351

EP - 369

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

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

IS - 4-5

ER -

Search for FCNC single top-quark production at √s=7 TeV with the ATLAS detector

Abstract

Keywords

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