W+W- production and triple gauge boson couplings                               
        at LEP energies up to 183 GeV                                          
  
A study of W-pair production in e+e- annihilations at LEP2 is presented,       
based on 877 W+W- candidates corresponding to an integrated luminosity of      
57 pb-1 at sqrt(s) = 183 GeV. Assuming that the angular distributions of       
the W-pair production and decay, as well as their branching fractions, are     
described by the Standard Model, the W-pair production cross-section is        
measured to be 15.43 +- 0.61 (stat.) +- 0.26 (syst.) pb. Assuming lepton       
universality and combining with our results from lower centre-of-mass          
energies, the W branching fraction to hadrons is determined to be              
67.9 +- 1.2 (stat.) +- 0.5 (syst.)%. The number of W-pair candidates and       
the angular distributions for each final state (qqlnu,qqqq,lnulnu) are used to 
determine the triple gauge boson couplings. After combining these values       
with our results from lower centre-of-mass energies we obtain                  
D(kappa_g)=0.11+0.52-0.37, D(g^z_1)=0.01+0.13-0.12 and lambda=-0.10+0.13-0.12, 
where the errors include both statistical and systematic uncertainties and     
each coupling is determined setting the other two couplings to the Standard    
Model value. The fraction of W bosons produced with a longitudinal             
polarisation is measured to be 0.242+-0.091(stat.)+-0.023(syst.). All these    
measurements are consistent with the Standard Model expectations.              
  
 Parallel session :5                   
 Plenary  session :6a