Preliminary measurement of the top quark pair production in the $\tau$ + jets final state with 20 $fb^{-1}$ of $pp$ collision data recorded at $\sqrt{s} = 8$ TeV with the ATLAS experiment

A preliminary measurement of the top quark pair production cross section in the final state containing a tau lepton that has decayed semi-hadronically and associated jets is presented. The signal events are required to have at least four jets with at least one that is a b-tagged jet. The analysis uses data with an integrated luminosity of 20 $fb^{-1}$ recorded by the ATLAS experiment in proton-proton collisions at the Large Hadron Collider at a center-of-mass energy of 8 TeV.