We present the results of a search for supersymmetry with gauge-mediated breaking and $\NONE\to\gamma\Gravitino$ in the $\gamma\gamma$+missing transverse energy final state. In 2.6$\pm$0.2 \invfb of $p{ \bar p}$ collisions at $\sqrt{ s}$$=$1.96 TeV recorded by the CDF II detector we observe no candidate events, consistent with a standard model background expectation of 1.4$\pm$0.4 events. We set limits on the cross section at the 95% C.L. and place the world's best limit of 149 \gevc on the \none mass at $\tau_{ \tilde{ \chi}_1^0}$$\ll$1 ns. We also exclude regions in the \none\ mass-lifetime plane for $\tau_{ \tilde{ \chi}_1^0}$$\lesssim$2 ns.
Categories: hep-ex