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

School of Physics and Astronomy

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

65 Scopus citations

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
State	Published - 12 Jun 2012

Funding

Funders	Funder number
AvH Foundation
Benoziyo Center , Israel
CEA-DSM/IRFU
Cantons of Bern and Geneva
DIP
DNSRC
DST/NRF
GNAS
MECTS
MERYS
MES of Russia
MSMT
MSSR
MSTD
MVZT
VSC CR
National Science Foundation	1119200
National Science Foundation
U.S. Department of Energy
Healthcare Georgia Foundation
Departamento Administrativo de Ciencia, Tecnología e Innovación (COLCIENCIAS)
School of Energy Resources, University of Wyoming
Türkiye Atom Enerjisi Kurumu
Arizona-Nevada Academy of Science
CERN
National Research Council
College of Arts and Sciences, University of Nebraska-Lincoln
Engineering Research Centers
Natural Sciences and Engineering Research Council of Canada
Science and Technology Facilities Council	PP/E002757/1, ST/F007337/1, ST/I003142/1, ST/I005803/1, ST/J004944/1, PP/E000347/1, ST/H001069/2, ST/K501840/1, ST/L001195/1, ST/H001026/1, ST/H001042/1, ST/I006080/1, ST/H001042/2, ST/I000186/1, ST/J004928/1, ST/K001361/1, ST/I003517/1, GRIDPP, ST/G502320/1, ST/K001310/1, ST/K001337/1, ST/H00100X/1, ST/L001144/1, ST/J002798/1, ST/K00073X/1, ST/H00100X/2, ST/K000705/1, ST/K001248/1, ST/I005811/1, PP/E003087/1, ST/J005460/1, PP/E000355/1, ST/H001093/2, ST/M001431/1, ST/K001418/1, ST/M001474/1, ST/H001093/1, ST/I003525/1, ST/M001512/1, PP/E003699/2, ST/H001026/2, PP/E003699/1, ST/J005576/1
Science and Technology Facilities Council
Leverhulme Trust
Royal Society
European Commission	IN2P3-CNRS
European Commission
Australian Research Council
Minerva Foundation
Deutsche Forschungsgemeinschaft
Japan Society for the Promotion of Science
Ministry of Education, Culture, Sports, Science and Technology
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
Danmarks Grundforskningsfond
German-Israeli Foundation for Scientific Research and Development
Canada Foundation for Innovation
Fundação de Amparo à Pesquisa do Estado de São Paulo
National Natural Science Foundation of China
National Science Council
Fundação para a Ciência e a Tecnologia
Bundesministerium für Bildung und Forschung
Comisión Nacional de Investigación Científica y Tecnológica
Agencia Nacional de Promoción Científica y Tecnológica
Ministerstvo Zdravotnictví Ceské Republiky
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
Foundation for Fundamental Research on Matter
General Secretariat for Research and Technology
Lundbeckfonden
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Ministry of Science and Technology
Joint Institute for Nuclear Research
Israel Science Foundation
Instituto Nazionale di Fisica Nucleare
Max-Planck-Gesellschaft
Javna Agencija za Raziskovalno Dejavnost RS
Ministerstwo Nauki i Szkolnictwa Wyższego
Ministerio de Ciencia e Innovación
Centre National pour la Recherche Scientifique et Technique
Bundesministerium für Wissenschaft und Forschung
State Atomic Energy Corporation ROSATOM
Marianne and Marcus Wallenberg Foundation
Ministry of Health of the Russian Federation

Keywords

FCNC
Heavy-quark production
Single top quark
Top physics

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10.1016/j.physletb.2012.05.022

Cite this

@article{d13da18291544a948ae7fdb7418ea697,

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 L. Barak and G. Bella and Y. Benhammou and E. Etzion and R. Lifshitz and Y. Oren and A. Soffer",

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

year = "2012",

month = jun,

day = "12",

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

language = "אנגלית",

volume = "712",

pages = "351--369",

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

issn = "0370-2693",

publisher = "Elsevier",

number = "4-5",

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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 - Barak, L.

AU - Bella, G.

AU - Benhammou, Y.

AU - Etzion, E.

AU - Lifshitz, R.

AU - Oren, Y.

AU - Soffer, 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 - http://www.scopus.com/inward/record.url?scp=85041997804&partnerID=8YFLogxK

U2 - 10.1016/j.physletb.2012.05.022

DO - 10.1016/j.physletb.2012.05.022

M3 - ???researchoutput.researchoutputtypes.contributiontojournal.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

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Keywords

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