Search for heavy Higgs bosons in the H $\to$ ${\tau }_{had}{\tau }_{had}$ channel with the ATLAS detector

In 2012, a scalar boson was found at CERN that is consistent with the properties of the Higgs boson predicted by the Standard Model of particle physics. Some theories, in particular supersymmetric models, also predict the existence of additional heavier neutral Higgs bosons. The decays of these heavy Higgs bosons to a pair of $\tau$ leptons can be siginificant because of the high mass of the $\tau$ lepton and additional effects of two-Higgs-doublet models that can enhance the coupling to down-type fermions. In this talk, details of the search for H $\to$ $\tau \tau$ in the fully hadronic channel using 36.1 fb${}^{-1}$ of proton-proton collision data taken with the ATLAS experiment at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV will be presented. Special emphasis will be placed on the background estimation of jets that are falsely identified as hadronically decaying $\tau$ leptons, which play an important role in many different analyses. This universal approach in determining the misidentification probability will also be presented.