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

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, e...

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Autor principal:	Aad, G.
Formato:	JOUR
Materias:	ATLAS Single top-quark Top quark W+t
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_03702693_v716_n1_p142_Aad
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

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spelling	todo:paper_03702693_v716_n1_p142_Aad2023-10-03T15:29:21Z Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV Aad, G. ATLAS Single top-quark Top quark W+t 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. © 2012 CERN JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_03702693_v716_n1_p142_Aad
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	ATLAS Single top-quark Top quark W+t
spellingShingle	ATLAS Single top-quark Top quark W+t Aad, G. Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV
topic_facet	ATLAS Single top-quark Top quark W+t
description	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. © 2012 CERN
format	JOUR
author	Aad, G.
author_facet	Aad, G.
author_sort	Aad, G.
title	Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV
title_short	Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV
title_full	Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV
title_fullStr	Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV
title_full_unstemmed	Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV
title_sort	evidence for the associated production of a w boson and a top quark in atlas at √s=7tev
url	http://hdl.handle.net/20.500.12110/paper_03702693_v716_n1_p142_Aad
work_keys_str_mv	AT aadg evidencefortheassociatedproductionofawbosonandatopquarkinatlasats7tev
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Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV

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