Photonic Events with Missing Energy in                                         
e+e- Collisions at sqrt(s) = 192-206 GeV                                       
  
Photonic events with missing energy have been observed in 192-206 GeV          
e+e- collisions using the OPAL detector at LEP. Results are presented          
for single-photon and acoplanar-photons event topologies.                      
Cross-section measurements are performed and the number of light               
neutrino species is measured.  Upper limits on cross-section times             
branching ratios for the class of new physics models e+ e- -> XX or            
XY are derived for stable and invisible Y.  Additional results are             
given for certain specific new physics models.                                 
  
 Parallel session :11                  
 Plenary  session :7a