Search for Heavy Higgs Bosons Decaying into Two Tau Leptons with the ATLAS Detector Using $pp$ Collisions at $\sqrt{s}=13\text{}\text{}\mathrm{TeV}$

A search for heavy neutral Higgs bosons is performed using the LHC Run 2 data, corresponding to an integrated luminosity of $139\text{}\text{}{\mathrm{fb}}^{-1}$ of proton-proton collisions at $\sqrt{s}=13\text{}\text{}\mathrm{TeV}$ recorded with the ATLAS detector. The search for heavy resonances is performed over the mass range 0.2–2.5 TeV for the ${\tau }^{+}{\tau }^{-}$ decay with at least one $\tau $-lepton decaying into final states with hadrons. The data are in good agreement with the background prediction of the standard model. In the ${M}_{h}^{125}$ scenario of the minimal supersymmetric standard model, values of $\mathrm{tan}\beta >8$ and $\mathrm{tan}\beta >21$ are excluded at the 95% confidence level for neutral Higgs boson masses of 1.0 and 1.5 TeV, respectively, where $\mathrm{tan}\beta $ is the ratio of the vacuum expectation values of the two Higgs doublets.