Search for the direct production of charginos and neutralinos in final states with tau leptons in $\sqrt{s} = 13$ TeV $pp$ collisions with the ATLAS detector

Two searches for the direct production of charginos and neutralinos with intermediate tau sleptons or Wh, in final states with at least two hadronically decaying $\tau$-leptons, are presented. The signal signature also requires an additional isolated light lepton in scenarios in which the charginos and neutralinos decay through an intermediate $W$ or Higgs boson. 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. Limits are derived in scenarios of $\tilde{\chi^{+}_{1} }\tilde{\chi^{-}_{1}}$ pair production and of combined $\tilde{\chi^{\pm}_{1} }\tilde{\chi^{0}_{2}}$ and $\tilde{\chi^{+} _{1}}\tilde{\chi^{-}_{1}}$ production in simplified models where the neutralinos and charginos decay solely via intermediate left-handed tau sleptons and tau sneutrinos. Chargino masses up to 970 GeV are excluded at 95 % confidence level in the scenario of direct production of $\tilde{\chi^{+}_{1} }\tilde{\chi^{-}_{1}}$ for a massless $\tilde{\chi^{0}_{1} }$. Degenerate $\tilde{\chi^{\pm}_{1}}$ and $\tilde{\chi^{0}_{2} }$ masses up to 1160 GeV are excluded in the case of production of $\tilde{\chi^{\pm}_{1} }\tilde{\chi^{0}_{2}}$ and $\tilde{\chi^{+}_{1} }\tilde{\chi^{-}_{1}}$ via tau sleptons decay assuming a massless $\tilde{\chi^{0}_{1} }$. For the $\tilde{\chi^{\pm}_{1} }\tilde{\chi^{0}_{2}}$ production via an intermediate Wh decay, masses up to 330 GeV are excluded for a massless $\tilde{\chi^{0}_{1} }$.