A search for high-mass resonances decaying to $\tau^{+}\tau^{-}$ in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

A search for high-mass resonances decaying into τ$^{+}$ τ$^{−}$ final states using proton-proton collisions at $ \sqrt{s}=8 $ TeV produced by the Large Hadron Collider is presented. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 19.5–20.3 fb$^{−1}$. No statistically significant excess above the Standard Model expectation is observed, 95% credibility upper limits are set on the cross section times branching fraction of Z′ resonances decaying into τ$^{+}$ τ$^{−}$ pairs as a function of the resonance mass. As a result, Z′ bosons of the Sequential Standard Model with masses less than 2.02 TeV are excluded at 95% credibility. The impact of the fermionic couplings on the Z′ acceptance is investigated and limits are also placed on a Z′ model that exhibits enhanced couplings to third-generation fermions.