Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector
Author(s)
Taylor, Frank E
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A search for single top-quark production via flavour-changing neutral current processes from gluon plus up- or charm-quark initial states in proton–proton collisions at the LHC is presented. Data collected with the ATLAS detector in 2012 at a centre-of-mass energy of 8 TeV and corresponding to an integrated luminosity of 20.3 fb[superscript −1] are used. Candidate events for a top quark decaying into a lepton, a neutrino and a jet are selected and classified into signal- and background-like candidates using a neural network. No signal is observed and an upper limit on the production cross-section multiplied by the t→Wb branching fraction is set. The observed 95 % CL limit is σ[subscript qg→t]×B(t→Wb)<3.4 pb and the expected 95 % CL limit is σ[subscript qg]→t×B(t→Wb)<2.9 pb. The observed limit can be interpreted as upper limits on the coupling constants of the flavour-changing neutral current interactions divided by the scale of new physics κ[subscript ugt]/Λ<5.8×10[superscript −3] TeV[superscript −1] and κ[subscrip cgt]/Λ<13×10[superscript −3] TeV and on the branching fractions B(t→ug)<4.0×10[superscript −5] and B(t→cg)<20×10[superscript −5] .
Date issued
2016-01Department
Massachusetts Institute of Technology. Department of PhysicsJournal
The European Physical Journal C
Publisher
Springer-Verlag
Citation
ATLAS Collaboration et al. “Search for Single Top-Quark Production via Flavour-Changing Neutral Currents at 8 TeV with the ATLAS Detector.” The European Physical Journal C 76.2 (2016): n. pag. © 2016 CERN for the benefit of the ATLAS collaboration
Version: Final published version
ISSN
1434-6044
1434-6052