Sensitivity to the single-top channels of the ATLAS experiment: study of systematic uncertainties

The measurement of the single top quark production cross section at the LHC will provide an accurate direct determination of the CKM Matrixelement Vtb. Theories beyond the Standard Model predict different modifications in the three channels, the t-, s- and Wt-channel, and it is therefore important to measure them separately. We present a study of the systematic uncertainties for the three channels. In particular the contributions from the parton distribution functions uncertainty is estimated, using different error parameterizations and Monte-Carlo generators for the hard process and showering. Other uncertainties include the renormalization and factorization scales and the b-fragmentation parameterisation