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Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Search for FCNC single top-quark production at root s=7 TeV with the ATLAS detector
AU - Barton, Adam
AU - Borissov, Guennadi
AU - Bouhova-Thacker, Eva
AU - Brodbeck, Timothy
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 - Ratoff, 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 - 2012/6/12
Y1 - 2012/6/12
N2 - A search for the production of single top-quarks via flavour-changing neutral-currents is presented. Data collected with the ATLAS detector at a centre-of-mass energy of root s = 7 TeV, corresponding to an integrated luminosity of 2.05 fb(-1), are used. Candidate events with a semileptonic top-quark decay signature are classified as signal- or background-like events by using several kinematic variables as input to a neural network. No signal is observed in the neural network output distribution and a Bayesian upper limit is placed on the production cross-section. The observed upper limit at 95% confidence level on the cross-section multiplied by the t -> Wb branching fraction is measured to be sigma(qg -> t) x B(t -> Wb) < 3.9 pb. This upper limit is converted using a model-independent approach into upper limits on the coupling strengths kappa(ugt)/Lambda < 6.9.10(-3) TeV-1 and kappa(cgt)/Lambda < 1.6.10(-2) TeV-1, where A is the new physics scale, and on the branching fractions B(t -> ug) < 5.7.10(-5) and B(t -> cg) < 2.7.10(-4).
AB - A search for the production of single top-quarks via flavour-changing neutral-currents is presented. Data collected with the ATLAS detector at a centre-of-mass energy of root s = 7 TeV, corresponding to an integrated luminosity of 2.05 fb(-1), are used. Candidate events with a semileptonic top-quark decay signature are classified as signal- or background-like events by using several kinematic variables as input to a neural network. No signal is observed in the neural network output distribution and a Bayesian upper limit is placed on the production cross-section. The observed upper limit at 95% confidence level on the cross-section multiplied by the t -> Wb branching fraction is measured to be sigma(qg -> t) x B(t -> Wb) < 3.9 pb. This upper limit is converted using a model-independent approach into upper limits on the coupling strengths kappa(ugt)/Lambda < 6.9.10(-3) TeV-1 and kappa(cgt)/Lambda < 1.6.10(-2) TeV-1, where A is the new physics scale, and on the branching fractions B(t -> ug) < 5.7.10(-5) and B(t -> cg) < 2.7.10(-4).
KW - Top physics
KW - Heavy-quark production
KW - FCNC
KW - Single top quark
U2 - 10.1016/j.physletb.2012.05.022
DO - 10.1016/j.physletb.2012.05.022
M3 - Journal article
VL - 712
SP - 351
EP - 369
JO - Physics Letters B
JF - Physics Letters B
SN - 0370-2693
IS - 4-5
ER -