Measurement of the Semileptonic Branching Ratio of                             
Charm Hadrons produced in Z0->cc Decays                                        
  
The inclusive charm hadron semileptonic branching fractions                    
B(c --> e) and B(c --> mu) in Z0 --> cc events have been                       
determined using 4.4 million hadronic Z0 decays collected                      
with the OPAL detector at LEP. A charm-enriched sample is                      
obtained by selecting events with reconstructed D* mesons.                     
Using leptons found in the hemisphere opposite that of the D* mesons,          
the semileptonic branching fractions of charm hadrons are measured to be       
                                                                               
B(c --> e )  = 0.103 +/- 0.009 +0.009 -0.008                                   
B(c --> mu ) = 0.090 +/- 0.007 +0.007 -0.006                                   
                                                                               
where the first errors are in each case statisical and the second              
systematic. Combining these measurements, the inclusive semileptonic           
branching fraction of charm hadrons is determined to be                        
                                                                               
B(c --> l)  =  0.095 +/- 0.006  (stat.) +0.007 - 0.007 (syst.).                
                                                                               
  
 Parallel session :7                   
 Plenary  session :3