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

ATLAS Collaboration

    Research output: Contribution to journalArticle

    53 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 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.

    Original languageEnglish
    Pages (from-to)351-369
    Number of pages19
    JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
    Volume712
    Issue number4-5
    DOIs
    Publication statusPublished - 2012 Jun 12

    Fingerprint

    quarks
    detectors
    cross sections
    neutral currents
    center of mass
    confidence
    kinematics
    luminosity
    signatures
    physics
    output
    decay
    energy

    Keywords

    • FCNC
    • Heavy-quark production
    • Single top quark
    • Top physics

    ASJC Scopus subject areas

    • Nuclear and High Energy Physics

    Cite this

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

    In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol. 712, No. 4-5, 12.06.2012, p. 351-369.

    Research output: Contribution to journalArticle

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    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 Kohei Yorita",
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    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 - Yorita, Kohei

    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

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    U2 - 10.1016/j.physletb.2012.05.022

    DO - 10.1016/j.physletb.2012.05.022

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    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

    SN - 0370-2693

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