First searches for single top quark production with ATLAS

Searches for single top quark production in the t- and Wt-channels have been carried out in 35 pb-1 of 7 TeV proton-proton collision data collected using the ATLAS detector during the 2010 LHC run. The t-channel analyses use events having a single electron or muon, two jets, and missing transverse energy. A cut-based analysis is used to extract a measurement of the production cross-section of sigma_t = 53 +46-36 pb, which translates to an upper limit of 162 pb at 95% confidence level. A cross-check analysis based on a multivariate likelihood function yields a similar result. Both results are consistent with the Standard Model prediction of 66 pb. The Wt-channel analyses use events containing one or two leptons, jets and missing transverse energy. A 95% confidence level upper limit is set on the Wt-channel production cross-section of sigma_Wt < 158 pb, corresponding to roughly 10 times the Standard Model prediction for this process.