Measurement of the top quark pair production cross section in pp collisions at $\sqrt{s}=7$ TeV in the ${\ell}+\tau$ channel and of the top quark branching ratios into channels with leptons and quarks with the ATLAS detector

A measurement of the inclusive cross section for top quark pair production in pp collisions using events with an isolated lepton (muon or electron) and a $\\tau$ lepton decaying to hadrons ($\\tau_{\\mathrm{had}}$) is reported. Measurements of the branching ratios of top quark decays into leptons and jets using events with $t \\overline{t}$ (top antitop) pairs are also reported. Events were recorded with the ATLAS detector at the LHC in pp collisions at a center-of-mass energy of 7 TeV. The collected data sample corresponds to an integrated luminosity of 4.6 ${\\mathrm{fb}}^{-1}$. The inclusive cross section measured using events with an isolated lepton and a $\\tau_{\\mathrm{had}}$ is $\\sigma_{t\\bar{t}} = 183\\pm 9 (stat.) \\pm 23 (syst.) \\pm 3 (lumi.) \\mathrm{pb.}$ The measured top quark branching ratios agree with the Standard Model predictions within the measurement uncertainties of a few percent.