Limits on extra dimensions and new particle production in the exclusive photon and missing energy signature in p(p)over-bar collisions at root s=1.8 TeV

The exclusive gammais not an element of(T) signal has a small standard model cross section and is thus a channel sensitive to new physics. This signature is predicted by models with a superlight gravitino or with large extra spatial dimensions. We search for such signals at the Collider Detector at Fermilab, using 87 pb(-1) of data at roots = 1.8 TeV, and extract 95% C.L. limits on these processes. A limit of 221 GeV is set on the scale \F\(1/2) in supersymmetric models. For 4, 6, and 8 extra dimensions, model-dependent limits on the fundamental mass scale M-D of 0.55, 0.58, and 0.60 TeV, respectively, are found. We also specify a "pseudo-model-independent" method of comparing the results to theoretical predictions.