Search for electroweak production of supersymmetric particles in final states with two $\tau$-leptons in $\sqrt{s}$ = 13 TeV $pp$ collisions with the ATLAS detector

Three searches for the direct production of $\tau$-sleptons or charginos and neutralinos in final states with at least two hadronically decaying $\tau$-leptons are presented. For chargino and neutralino production, decays via intermediate $\tau$-sleptons 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 supersymmetric particle mass limits at 95% confidence level are obtained in simplified models. For direct production of $\stackrel{~}{}{\chi }_1^{+}\stackrel{~}{}{\chi }_1^{-}$, chargino masses are excluded up to 970 GeV, while $\stackrel{~}{}{\chi }_1^{\pm }$ and $\stackrel{~}{}{\chi }_2^0$ masses up to 1160 GeV (330 GeV) are excluded for $\stackrel{~}{}{\chi }_1^{\pm }\stackrel{~}{}{\chi }_2^0$/$\stackrel{~}{}{\chi }_1^{+}\stackrel{~}{}{\chi }_1^{-}$ production with subsequent decays via $\tau$-sleptons ($W$ and $h$ bosons). Masses of $\tau$-sleptons up to 500 GeV are excluded for mass degenerate $\stackrel{~}{}{\tau }_{L,R}$ scenarios and up to 425 GeV for $\stackrel{~}{}{\tau }_L$-only scenarios. Sensitivity to $\stackrel{~}{}{\tau }_R$-only scenarios from the ATLAS experiment is presented here for the first time, with $\stackrel{~}{}{\tau }_R$ masses excluded up to 350 GeV.