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

ATLAS Collaboration

doi:10.1016/j.physletb.2012.08.011

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

ATLAS Collaboration

Fakultät für Mathematik und Physik
University of Freiburg
University of Oklahoma
The Barcelona Institute of Science and Technology
Laboratoire de l'Accélérateur Linéaire
Section de Physique
University of Geneva
Azerbaijan Academy of Sciences
Oklahoma State University
Department of Physics and Astronomy
Michigan State University
University of Toronto
Tel Aviv University
Universite Paris-Saclay
Sezione INFN di Milano
University of Milano
Sezione di Roma
Abdus Salam International Centre for Theoretical Physics
Faculty of Physics and Applied Computer Science
Agh University of Science and Technology Faculty of Computer Science
Brookhaven National Laboratory Physics Department
Department of Physics
Hampton University
Yale University
Fakultät für Physik
Universität München
School of Physics and Astronomy
Queen Mary University of London
Rutherford Appleton Laboratory
Department of Physics
Brandeis University
LIP - Lisboa
Departamento de Fisica Teorica y del Cosmos and CAFPE
University of Granada
Johannes Gutenberg University
Boston University
Departments of Physics & Astronomy and Chemistry
Stony Brook University
Physics Department
University of Texas
INFN Roma Tor Vergata
University of Rome “Tor Vergata”
Department of Physics
Bogazici University
Department of Physics
Lund University
International Center for Elementary Particle Physics and Department of Physics
University of Tokyo
P.N. Lebedev Physical Institute of the Russian Academy of Sciences
Kobe University
State University of New York Albany
Department of Physics
Royal Holloway University of London
University of Victoria
Laboratoire de Physique Subatomique et de Cosmologie de Grenoble
European Organization for Nuclear Research
Joint Institute for Nuclear Research, Dubna
Horia Hulubei National Institute of Physics and Nuclear Engineering
Physics Department
National Technical University of Athens
Dipartimento di Chimica
and Physics University of Udine
Department of Physics
Humboldt-Universität zu Berlin
University of Pennsylvania School of Arts and Sciences

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

107 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 σ_Wt=16.8±2.9 (stat)±4.9 (syst) pb, in good agreement with the Standard Model expectation. From this result the CKM matrix element |V_tb|=1.03_−0.19 ^+0.16 is derived assuming that the Wt production through |V_ts| and |V_td| is small.

Original language	English
Pages (from-to)	142-159
Number of pages	18
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	716
Issue number	1
DOIs	https://doi.org/10.1016/j.physletb.2012.08.011
Publication status	Published - 17 Sept 2012
Externally published	Yes

Keywords

ATLAS
Single top-quark
Top quark
W+t

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10.1016/j.physletb.2012.08.011

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@article{20698e96bb84475cbfd5054174868f8c,

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 \{De La Taille\}, C. and O. Simard",

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

year = "2012",

month = sep,

day = "17",

doi = "10.1016/j.physletb.2012.08.011",

language = "English",

volume = "716",

pages = "142--159",

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

issn = "0370-2693",

publisher = "Elsevier B.V.",

number = "1",

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TY - JOUR

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 - De La Taille, C.

AU - Simard, O.

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

U2 - 10.1016/j.physletb.2012.08.011

DO - 10.1016/j.physletb.2012.08.011

M3 - Article

AN - SCOPUS:85042037870

SN - 0370-2693

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

IS - 1

ER -

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

Abstract

Keywords

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