Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV

ATLAS Collaboration

    Research output: Contribution to journalArticle

    78 Citations (Scopus)

    Abstract

    This Letter presents evidence for the associated production of a W boson and a top quark using 2.05 fb−1 of pp collision data at s=7TeV accumulated with the ATLAS detector at the LHC. The analysis is based on the selection of the dileptonic final states with events featuring two isolated leptons, electron or muon, with significant transverse missing momentum and at least one jet. An approach based on boosted decision trees has been developed to improve the discrimination of single top-quark Wt events from background. A template fit to the final classifier distributions is performed to determine the cross-section. The result is incompatible with the background-only hypothesis at the 3.3σ level, the expected sensitivity assuming the Standard Model production rate being 3.4σ. The corresponding cross-section is determined and found to be σWt=16.8±2.9 (stat)±4.9 (syst) pb, in good agreement with the Standard Model expectation. From this result the CKM matrix element |Vtb|=1.03−0.19 +0.16 is derived assuming that the Wt production through |Vts| and |Vtd| is small.

    Original languageEnglish
    Pages (from-to)142-159
    Number of pages18
    JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
    Volume716
    Issue number1
    DOIs
    Publication statusPublished - 2012 Sep 17

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    bosons
    quarks
    cross sections
    classifiers
    discrimination
    leptons
    muons
    templates
    momentum
    collisions
    sensitivity
    detectors
    matrices
    electrons

    Keywords

    • ATLAS
    • Single top-quark
    • Top quark
    • W+t

    ASJC Scopus subject areas

    • Nuclear and High Energy Physics

    Cite this

    Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV. / ATLAS Collaboration.

    In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol. 716, No. 1, 17.09.2012, p. 142-159.

    Research output: Contribution to journalArticle

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    title = "Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV",
    abstract = "This Letter presents evidence for the associated production of a W boson and a top quark using 2.05 fb−1 of pp collision data at s=7TeV accumulated with the ATLAS detector at the LHC. The analysis is based on the selection of the dileptonic final states with events featuring two isolated leptons, electron or muon, with significant transverse missing momentum and at least one jet. An approach based on boosted decision trees has been developed to improve the discrimination of single top-quark Wt events from background. A template fit to the final classifier distributions is performed to determine the cross-section. The result is incompatible with the background-only hypothesis at the 3.3σ level, the expected sensitivity assuming the Standard Model production rate being 3.4σ. The corresponding cross-section is determined and found to be σWt=16.8±2.9 (stat)±4.9 (syst) pb, in good agreement with the Standard Model expectation. From this result the CKM matrix element |Vtb|=1.03−0.19 +0.16 is derived assuming that the Wt production through |Vts| and |Vtd| is small.",
    keywords = "ATLAS, Single top-quark, Top quark, W+t",
    author = "{ATLAS Collaboration} and G. Aad and B. Abbott and J. Abdallah and {Abdel Khalek}, S. and Abdelalim, {A. A.} 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 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 Allbrooke, {B. M.M.} and Kohei Yorita",
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    T1 - Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV

    AU - ATLAS Collaboration

    AU - Aad, G.

    AU - Abbott, B.

    AU - Abdallah, J.

    AU - Abdel Khalek, S.

    AU - Abdelalim, A. 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 - 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 - Allbrooke, B. M.M.

    AU - Yorita, Kohei

    PY - 2012/9/17

    Y1 - 2012/9/17

    N2 - This Letter presents evidence for the associated production of a W boson and a top quark using 2.05 fb−1 of pp collision data at s=7TeV accumulated with the ATLAS detector at the LHC. The analysis is based on the selection of the dileptonic final states with events featuring two isolated leptons, electron or muon, with significant transverse missing momentum and at least one jet. An approach based on boosted decision trees has been developed to improve the discrimination of single top-quark Wt events from background. A template fit to the final classifier distributions is performed to determine the cross-section. The result is incompatible with the background-only hypothesis at the 3.3σ level, the expected sensitivity assuming the Standard Model production rate being 3.4σ. The corresponding cross-section is determined and found to be σWt=16.8±2.9 (stat)±4.9 (syst) pb, in good agreement with the Standard Model expectation. From this result the CKM matrix element |Vtb|=1.03−0.19 +0.16 is derived assuming that the Wt production through |Vts| and |Vtd| is small.

    AB - This Letter presents evidence for the associated production of a W boson and a top quark using 2.05 fb−1 of pp collision data at s=7TeV accumulated with the ATLAS detector at the LHC. The analysis is based on the selection of the dileptonic final states with events featuring two isolated leptons, electron or muon, with significant transverse missing momentum and at least one jet. An approach based on boosted decision trees has been developed to improve the discrimination of single top-quark Wt events from background. A template fit to the final classifier distributions is performed to determine the cross-section. The result is incompatible with the background-only hypothesis at the 3.3σ level, the expected sensitivity assuming the Standard Model production rate being 3.4σ. The corresponding cross-section is determined and found to be σWt=16.8±2.9 (stat)±4.9 (syst) pb, in good agreement with the Standard Model expectation. From this result the CKM matrix element |Vtb|=1.03−0.19 +0.16 is derived assuming that the Wt production through |Vts| and |Vtd| is small.

    KW - ATLAS

    KW - Single top-quark

    KW - Top quark

    KW - W+t

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    U2 - 10.1016/j.physletb.2012.08.011

    DO - 10.1016/j.physletb.2012.08.011

    M3 - Article

    VL - 716

    SP - 142

    EP - 159

    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

    IS - 1

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