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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Evidence for the associated production of a W boson and a top quark in ATLAS at root s=7 TeV
AU - Barton, Adam
AU - Borissov, Guennadi
AU - Bouhova-Thacker, Eva
AU - Chilingarov, Alexandre
AU - Davidson, Ruth
AU - de Mora, Lee
AU - Dearnaley, William
AU - Fox, Harald
AU - Henderson, Robert
AU - Hughes, Gareth
AU - Jones, Roger William Lewis
AU - Kartvelishvili, Vakhtang
AU - Long, Robin
AU - Love, Peter
AU - Smizanska, Maria
AU - Walder, James
AU - The ATLAS collaboration
N1 - This article is published Open Access at sciencedirect.com. It is distributed under the terms of the Creative Commons Attribution License 3.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.
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 root s = 7 TeV 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 3.3 sigma level, the expected sensitivity assuming the Standard Model production rate being 3.4 sigma. The corresponding cross-section is determined and found to be sigma(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 vertical bar V-tb vertical bar = 1.03(-0.19)(+0.16) is derived assuming that the Wt production through vertical bar V-ts vertical bar and vertical bar V-td vertical bar 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 root s = 7 TeV 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 3.3 sigma level, the expected sensitivity assuming the Standard Model production rate being 3.4 sigma. The corresponding cross-section is determined and found to be sigma(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 vertical bar V-tb vertical bar = 1.03(-0.19)(+0.16) is derived assuming that the Wt production through vertical bar V-ts vertical bar and vertical bar V-td vertical bar is small.
KW - ATLAS
KW - Top quark
KW - W+t
KW - Single top-quark
U2 - 10.1016/j.physletb.2012.08.011
DO - 10.1016/j.physletb.2012.08.011
M3 - Journal article
VL - 716
SP - 142
EP - 159
JO - Physics Letters B
JF - Physics Letters B
SN - 0370-2693
IS - 1
ER -