Search for Neutral Higgs Bosons in e+e- Collisions at sqrt(s) ~ 189 GeV        
  
A search for neutral Higgs bosons has been performed                           
with the OPAL detector at LEP, using approximately                             
170 pb^{-1} of e+e- collision data                                             
collected at sqrt{s} ~ 189 GeV.                                                
Searches have been performed for the Standard Model (SM) process               
e+e- -> HZ  and the MSSM processes e+e- -> hZ, Ah.                             
The searches are sensitive to the                                              
bb and tautau decay modes of the Higgs bosons, and also to                     
the MSSM decay mode h->AA.                                                     
OPAL search results at                                                         
lower centre-of-mass energies have been incorporated                           
in the limits we set, which are valid at the 95 % confidence level.            
For the SM Higgs boson, we obtain a lower mass bound of 91.0 GeV.              
In the MSSM, our limits are                                                    
mh>74.8 GeV and mA>76.5 GeV, assuming                                          
tan(beta)>1, that the mixing of the scalar top quarks is either zero or        
maximal, and that the soft SUSY-breaking masses are 1 TeV.                     
For the case of zero scalar top mixing, we exclude values of tan(beta)         
between 0.72 and 2.19.                                                         
  
 Parallel session :11                  
 Plenary  session :7a