Measurement of the Single Top-Quark Production Cross Section with the ATLAS Detector

We present three single top analyses carried out with 0.70fb-1 of integrated luminosity collected by the ATLAS detector during the 2011 LHC run. The t-channel production cross section is measured by two different techniques, a cut-based approach and a multivariate discriminant constructed with a neural network. The cut-based analysis combines 2- and 3-jet events and measures sigma_t = 90 +32 -22 pb. The search for Wt events in the dilepton channel results in a 95% CL upper limit on Wt-channel single top-quark production of sigma< 39 pb. Finally, for the single top channel with the lowest expected production cross section, the s-channel, an upper limit at 95% CL of sigma_s< 26.5 pb is obtained using a cut-based approach.