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 $\tilde~{ \chi}^+_1\tilde~{ \chi}^-_1$, chargino masses are excluded up to 970 GeV, while $\tilde~{ \chi}^{ \pm}_1$ and $\tilde~{ \chi}^0_2$ masses up to 1160 GeV (330 GeV) are excluded for $\tilde~{ \chi}^{ \pm}_1\tilde~{ \chi}^0_2$/$\tilde~{ \chi}^+_1\tilde~{ \chi}^-_1$ production with subsequent decays via $\tau$-sleptons ($W$ and $h$ bosons). Masses of $\tau$-sleptons up to 500 GeV are excluded for mass degenerate $\tilde~{ \tau}_{ L,R}$ scenarios and up to 425 GeV for $\tilde~{ \tau}_L$-only scenarios. Sensitivity to $\tilde~{ \tau}_R$-only scenarios from the ATLAS experiment is presented here for the first time, with $\tilde~{ \tau}_R$ masses excluded up to 350 GeV.
Categories: hep-ex