Measurement of triple gauge couplings using                                    
photonic events with missing energy at sqrt(s) = 189 GeV                       
  
   The triple gauge boson couplings between two W bosons and a photon have     
   been studied using photonic events with missing energy. The data            
   sample was obtained at LEP with the OPAL detector. The centre of mass       
   energy = 189 GeV with a total luminosity of 187.2 pb^-1.                    
   Constraints on the gauge coupling parameters                                
   Delta kappa_gamma and lambda_gamma have been determined                     
   by fitting the differential cross section in bins of energy and             
   cos(theta).                                                                 
  
 Parallel session :5                   
 Plenary  session :6a