Multi-boson effects and the normalization of the two-pion correlation   function
  The two-pion correlation function can be defined as a ratio of either the measured momentum distributions or the normalized momentum space probabilities. We show that the first alternative avoids certain ambiguities since then the normalization of the two-pion correlator contains important information on the multiplicity distribution of the event ensemble which is lost in the second alternative. We illustrate this explicitly for specific classes of event ensembles. 
Q. H. Zhang, P. Scotto and U. Heinz (Regensburg University)