Preliminary search for $\tilde{\chi}_1^0 \rightarrow \tilde{\tau} \tau$ in light gravitino scenarios

Lightest neutralino pair production is searched for within the Gauge Mediated Symmetry Breaking model context. It is assumed that the lightest neutralino is the NNLSP and that the ~ is the NLSP. Data at 161 and 172 GeV center of mass energy are analysed and no candidate is found. Limits on the lightest neutralino pair production cross section are set at 95% CL, as a function of m~0 1 and m~.