Search for Single Top Quark Production via Flavour Changing Neutral Currents in ATLAS data.

In the Standard Model (SM) transitions between top quarks and other quark flavours mediated by neutral gauge bosons, so-called Flavour Changing Neutral Currents (FCNC), are forbidden at tree level and highly suppressed at higher orders due to the Glashow-Iliopoulos-Maiani (GIM) mechanism. However, there exist several new physics models, which significantly enhance rates of FCNC processes compared to the Standard Model predictions. Therefore any observation of such processes would be a strong indicator for new physics. Data collected with the ATLAS detector are used and searched for FCNC events in which a light quark (u or c) interacts with a gluon to produce a single top quark. Candidate events of top quarks decaying leptonically are selected and classified into signal- and background-like events using a neural network. As no signal is observed, new upper limits on the production cross-sections multiplied by the t $\rightarrow$ Wb branching fraction as well as on the coupling strengths and branching ratios of the involved FCNC interactions are placed.