Measurement of the top-quark pair production cross-section using final states with an electron or a muon and a hadronically decaying τ-lepton

A measurement of the top-quark pair production cross-section is reported using proton-proton collision data at $\sqrt{s}=7\text{TeV}$ recorded by ATLAS experiment at the Large Hadron Collider. Events are extracted from 2.05 fb⁻¹ of data by requiring an isolated electron or muon, a large missing transverse momentum, two or more energetic jets and a hadronically decaying τ-lepton. The measured cross-section, ${\sigma }_{t\overline{t}}=186\pm 13\left(\text{stat.}\right)\pm 20\left(\text{syst.}\right)\pm 7\left(\text{lumi.}\right)$ pb, is in good agreement with the Standard Model prediction.