Search for electroweak production of supersymmetric particles in final states with two τ-leptons in √s = 13 TeV pp collisions with the ATLAS detector

Three searches for the direct production of staus or charginos and neutralinos in final states with at least two hadronically decaying τ-leptons are presented. For chargino and neutralino production, decays via intermediate staus or W and h bosons are considered. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of 139 fb⁻¹, recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV. No significant deviation from the expected Standard Model background is observed and SUSY particle mass limits at 95% confidence level are obtained in simplified models. For direct production of ~χ+1~χ−1, chargino masses are excluded up to 970 GeV, while ~χ^±₁ and ~χ⁰₂ masses up to 1160 GeV (330 GeV) are excluded for ~χ^±₁~χ⁰₂/~χ⁺₁~χ⁻₁ production with subsequent decays via staus (W and h bosons). Stau masses up to 500 GeV are excluded for mass degenerate ~τ_L,R scenarios and up to 425 GeV for ~τ_L-only scenarios. Sensitivity to ~τ_R-only scenarios from the ATLAS experiment is presented here for the first time, with ~τ_R masses excluded up to 350 GeV.