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

University at Albany, Stony Brook University

University of Freiburg
University of Oklahoma
Institute for High Energy Physics
Laboratoire de l'Accélérateur Linéaire
University of Geneva
Azerbaijan National Academy of Sciences
Oklahoma State University
Michigan State University
University of Toronto
Tel Aviv University
Centre d'Etudes de Saclay
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
Ludwig Maximilian University of Munich
Queen Mary University of London
Rutherford Appleton Laboratory
Brandeis University
Laboratório de Instrumentação e Física Experimental de Partículas
University of Granada
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
P.N. Lebedev Physical Institute of the Russian Academy of Sciences
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 Udine
Humboldt University of Berlin
University of Pennsylvania
IThemba Labs
Department of Physics
University of South Africa
Cadi Ayyad University
Moroccan Foundation for Advanced Science Innovation and Research (MAScIR)
Dep Física and CEFITEC of Faculdade de Ciências e Tecnologia
NOVA University Lisbon
University of Freiburg
University of Oklahoma
IN2P3/CNRS
Azerbaijan National Academy of Sciences
Oklahoma State University
Michigan State University
University of Toronto
Tel Aviv University
National Institute for Nuclear Physics
Abdus Salam International Centre for Theoretical Physics
United States Department of Energy
Yale University
Ludwig Maximilian University of Munich
Queen Mary University of London
Rutherford Appleton Laboratory
Brandeis University
Laboratório de Instrumentação e Física Experimental de Partículas
Johannes Gutenberg University Mainz
Boston University
Stony Brook University
University of Rome Tor Vergata
Lund University
P.N. Lebedev Physical Institute of the Russian Academy of Sciences
SUNY Albany
Royal Holloway University of London
University of Victoria BC
CERN
Joint Institute for Nuclear Research
Horia Hulubei National Institute of Physics and Nuclear Engineering
National Technical University of Athens
Department of Physics
University of South Africa
Cadi Ayyad University
Dep Física and CEFITEC of Faculdade de Ciências e Tecnologia

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

107 Scopus citations

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
State	Published - Sep 17 2012

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{dde54b200de5473db2643b75c1731c5f,

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 J. Ernst and V. Jain and \{Da Via\}, C. and V. Dao and J. Hobbs and J. Jia and G. Piacquadio and D. Tsybychev",

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",

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 - Ernst, J.

AU - Jain, V.

AU - Da Via, C.

AU - Dao, V.

AU - Hobbs, J.

AU - Jia, J.

AU - Piacquadio, G.

AU - Tsybychev, D.

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

UR - https://www.scopus.com/pages/publications/85042037870

U2 - 10.1016/j.physletb.2012.08.011

DO - 10.1016/j.physletb.2012.08.011

M3 - Article

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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