Associated Higgs Boson Top-Quark production channel $t\bar tH \rightarrow l^{\pm}l^{\pm}+{\tau_\textrm{had}}$ at $\sqrt{13}$ TeV with the ATLAS experiment

The measurement of the associated production of a Higgs boson with a pair of top quarks is a direct determination of the top-Yukawa coupling at tree-level, which can be compared with the indirect determination in the loop-production in gluon-gluon fusion. The decay channel of the system with several leptons (multi-lepton channel), and jets, gives high sensitivity. The focus of the analysis is the sub-channel with two same-sign light leptons (electrons or muons) and a hadronically decaying tau lepton: $\rm ttH \rightarrow 2\ell + 1 \tau_{had}$. In particular the background estimate from top-antitop reactions is discussed. The analysis uses the data set recorded by ATLAS from LHC Run-II during 2015 and 2016 at $\sqrt{13}$ TeV proton-proton collisions.