Prospects for searches for staus, charginos and neutralinos at the high luminosity LHC with the ATLAS Detector

The current searches at the LHC have yielded sensitivity to weakly-interacting supersymmetric particles in the hundreds of GeV mass range and the reach at the high-luminosity phase of the LHC is expected to significantly extend beyond the current limits. This document presents example benchmark studies for stau pair production ($\tilde{\tau}^+\tilde{\tau}^-$) using a final state with two hadronically decaying taus, chargino pair production ($\tilde{\chi}^{+}_1\tilde{\chi}^{-}_1$) using a final state with two leptons, and chargino-neutralino production ($\tilde{\chi}^{\pm}_1\tilde{\chi}^{0}_2$) using either a $\ell\ell\ell$ or $\ell bb$ final state. A parameterised simulation of the ATLAS detector at a centre-of-mass energy of 14 TeV is used. Expected results are shown for an integrated luminosity of 3000 fb$^{-1}$, where the discovery regions exceed the current limits on SUSY particle masses set at the LHC by hundreds of GeV. The discovery potential at the HL-LHC reaches stau masses of 530 GeV and chargino masses of 660 GeV, for $\tilde{\tau}^+\tilde{\tau}^-$ and $\tilde{\chi}^{+}_1\tilde{\chi}^{-}_1$ production, respectively. For $\tilde{\chi}^{\pm}_1\tilde{\chi}^{0}_2$ production, the discovery region reaches up to 920 GeV (1080 GeV) in $\tilde{\chi}^{\pm}_1$ and $\tilde{\chi}^{0}_2$ masses, where the $\tilde{\chi}^{0}_2$ decays via the Standard Model $Z$ ($h$) boson. The 95% CL expected exclusion potentials at the HL-LHC reach ~200 GeV higher in mass than the discovery potentials for all cases considered.