Measurement of the B+ and B0 Lifetimes and Search                              
for CP(T) Violation using Reconstructed Secondary                              
Vertices                                                                       
  
The lifetimes of the B+ and B0 mesons, and their ratio,                        
have been measured in the OPAL experiment using Z->bb events with              
well-reconstructed charged and neutral secondary vertices.                     
The results are:                                                               
                                                                               
tau_B+        = 1.643 +- 0.037 +- 0.025 ps,                                    
tau_B0        = 1.523 +- 0.057 +- 0.053 ps,                                    
tau_B+/tau_B0 = 1.079 +- 0.064 +- 0.041.                                       
                                                                               
CP and CPT violating effects have been searched for by comparison              
of inclusive b and bbar hadron decays. The CP violation                        
parameter Re(epsilon_B) is measured to be 0.001 +-0.014 +-0.003                
and the fractional  difference between b and bbar hadron lifetimes is          
measured to be -0.001+-0.012+-0.008.                                           
  
 Parallel session :7                   
 Plenary  session :3