Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector

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?8TeV?and corresponding to an integrated luminosity of?20.3fb?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?σqg→t×B(t→Wb)<3.4pb?and the expected?95%?CL limit is?σqg→t×B(t→Wb)<2.9pb. 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?κugt/Λ<5.8×10?3TeV?1?and?κcgt/Λ<13×10?3TeV?1?and on the branching fractions?B(t→ug)<4×10?5?and?B(t→cg)<20×10?5.