Stau searches and measurements with the ILD concept at the International Linear Collider

One of the most interesting channels to search for SUSY is the direct pair-production of the $\tau$-lepton superpartner, $\tilde{\tau }$. The $\tilde{\tau }$ is with high probability the lightest of the scalar leptons, so one of the first SUSY particles that can be observerd, and the signature of $\tilde{\tau }$ pair production signal events is one of the most difficult ones, yielding to the worst'' and so most global scenario for the searches. Analysis performed at LEP set the current model-independent $\widetildeτ$ limits, suffering from the low energy of this facility. Only under strong model assumptions, these limits are extended to higher masses by LHC studies. In this contribution we show the capability of the ILC, a future electron-positron collider with energy up to 1 TeV, for determining $\widetildeτ$ exclusion/discovery limits in a model-independent way, including an overview of the current state-of-the-art. The determination of the worst’’ scenario for $\tilde{\tau }$ exclusion/discovery, taking into account the effect of the $\tilde{\tau }$ mixing on $\tilde{\tau }$ production cross-section and efficiency, is also presented. For selected benchmarks, the prospect for measuring masses and polarised cross-sections will be shown. The studies were done studying events passed through the full detector simulation and reconstruction procedures of the International Large Detector (ILD) concept at the ILC. The simulation included all SM backgrounds, as well as the machine induced ones.