Search for FCNC single top-quark production at root s=7 TeV with the ATLAS detector
Number of Authors: 3041
2012 (English)In: Physics Letters B, ISSN 0370-2693, Vol. 712, no 4-5, 351-369 p.Article in journal (Refereed) Published
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). (C) 2012 CERN.
Place, publisher, year, edition, pages
Elsevier, 2012. Vol. 712, no 4-5, 351-369 p.
Top physics, Heavy-quark production, FCNC, Single top quark
IdentifiersURN: urn:nbn:se:kth:diva-99305DOI: 10.1016/j.physletb.2012.05.022ISI: 000305378200006ScopusID: 2-s2.0-84861482932OAI: oai:DiVA.org:kth-99305DiVA: diva2:541868
Author count: 3041 QC 201207252012-07-252012-07-25Bibliographically approved