Acciarri, M (reprint author), Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy.
An analysis of single and multi-photon events with missing energy is performed using data collected with the L3 detector at LEP at centre-of-mass energies around 183 GeV, for a total of 55.3 pb(-1) of integrated luminosity. The results obtained are in good agreement with the Standard Model prediction and are used to derive the value for the e(+)e(-) --> v (v) over bar gamma(gamma) cross section as well as upper limits on ness sections of new physics processes. Several interpretations in supersymmetric models providing new limits on the masses of the lightest neutralino and of the gravitino are presented. (C) 1998 Elsevier Science B.V. All rights reserved.