Tau polarization in SUSY cascade decays at LHC

We explore how the polarization of the tau leptons in the cascade decay $\tilde{q}\to q{\tilde{\chi }}_2^0\to q\tau \tilde{\tau }\to q\tau \tau {\tilde{\chi }}_1^0$ can be exploited to study mixing properties of neutralinos and staus. We present details of the analysis including experimental effects such as transverse momentum cuts for the $\tau \to \pi \nu$ decay mode, and show that the di-pion invariant mass distribution provides valuable information on their properties.