Measurement of the top quark pair production cross section in pp collisions at $sqrt{s}$=7 TeV in $\mu$ + $\tau$ final states with ATLAS

A measurement of the cross section of top quark pair production in proton$-$proton collisions at a center-of-mass of 7 TeV at the LHC using events with an isolated $mu$ and a $ au$ lepton decaying hadronically is reported. In addition to a $mu$ and a $ au$ lepton, large missing transverse energy and two or more jets are required. At least one of the jets must be identified as originating from a $b$ quark. To identify $ au$ leptons, the analysis uses a multivariate technique based on boosted decision trees. A data sample collected by ATLAS corresponding to an integrated luminosity of 1.08 ${ m fb}^{-1}$ yields [ sigma_{tar{t}} = 142pm 21 stat pm^{20}_{16}syst pm 5 ( ext{lumi.}) ext{pb.} ]