Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36.1 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

A search for neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) and for heavy neutral $Z^{\prime}$ bosons is performed using a data sample corresponding to an integrated luminosity of 36.1 fb$^{-1}$ from proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded by the ATLAS detector at the LHC during 2015 and 2016. The heavy resonance is assumed to decay to $\tau^+\tau^-$ with at least one tau lepton decaying to final states with hadrons and a neutrino. The search is performed in the mass range of 0.2-2.25 TeV for the MSSM neutral Higgs bosons and 0.2-4.0 TeV for the heavy neutral $Z^{\prime}$ boson. The data are in good agreement with the background predicted by the Standard Model. The results are interpreted in MSSM and $Z^{\prime}$ benchmark scenarios. In the context of the hMSSM scenario, the most stringent limits for the combined search exclude $\tan\beta$ > 1.0 for $m_{A}$ = 0.25 TeV and $\tan\beta$ > 45 for $m_{A}$ = 1.5 TeV at the 95% confidence level (CL). For the Sequential Standard Model, a $Z^{\prime}_\mathrm{SSM}$ mass up to 2.42 TeV is excluded at 95% CL and masses up to 2.25-2.60 TeV are excluded for a $Z^{\prime}_\mathrm{SFM}$ of the Strong Flavour Model.