Search for Heavy Long-Lived Particles that Decay to Photons at CDF II

We present the first search for heavy, long-lived particles that decay to photons at a hadron collider. We use a sample of {gamma} + jet + missing transverse energy events in pp collisions at {radical}(s)=1.96 TeV taken with the CDF II detector. Candidate events are selected based on the arrival time of the photon at the detector. Using an integrated luminosity of 570 pb{sup -1} of collision data, we observe 2 events, consistent with the background estimate of 1.3{+-}0.7 events. While our search strategy does not rely on model-specific dynamics, we set cross section limits in a supersymmetric model with {chi}-tilde{sub 1}{sup 0}{yields}{gamma}G-tilde and place the world-best 95% C.L. lower limit on the {chi}-tilde{sub 1}{sup 0} mass of 101 GeV/c{sup 2} at {tau}{sub {chi}-tilde{sub 1}{sup 0}}=5 ns.