Search for FCNC single top-quark production at √s = 7 TeV with the ATLAS detector
Author(s)Taylor, Frank E.
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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 √s = 7 TeV, corresponding to an integrated luminosity of 2.05 fb[superscript −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 σ[subscript qg→t]×B(t→Wb)<3.9 pb. This upper limit is converted using a model-independent approach into upper limits on the coupling strengths κ[subscript ugt]/Λ<6.9⋅10[superscript −3] TeV[superscript −1] and κ[subscript cgt]/Λ<1.6⋅10[superscript −2] TeV[superscript −1], where Λ is the new physics scale, and on the branching fractions B(t→ug)<5.7⋅10[superscript −5] and B(t→cg)<2.7⋅10[superscript −4].
DepartmentMassachusetts Institute of Technology. Department of Physics
Physics Letters B
Aad, G., B. Abbott, J. Abdallah, A.A. Abdelalim, A. Abdesselam, O. Abdinov, B. Abi, et al. “Search for FCNC Single Top-Quark Production at √s = 7 TeV with the ATLAS Detector.” Physics Letters B 712, no. 4–5 (June 2012): 351–369. © 2012 CERN
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