Transverse and longitudinal Bose-Einstein correlations in hadronic Z0 decay    
  
Bose-Einstein correlations in pairs of identical charged pions,                
produced in a sample of 4.3 million Z0 hadronic decays, are                    
studied as a function of the three components of the momentum                  
difference transverse and longitudinal to the thrust direction                 
of the event. A significant difference between the transverse                  
and longitudinal dimensions is observed,                                       
indicating that the emitting source, as observed in the                        
Longitudinally CoMoving System, has an elongated shape.                        
Measurements of the effective transverse and longitudinal                      
sizes of the source are presented and                                          
discussed in the context of a recent model of                                  
Bose-Einstein correlations based on string fragmentation.                      
  
 Parallel session :2                   
 Plenary  session :12