Multi-pion correlations in two-pion interferometry

The influence of multi-pion correlations on two-pion interferometry analysis in multi-pion event can be expressed as the ratio of a multi-pion correlation factor for the sample of like-pion pairs to a residual correlation factor for the reference sample. Although these two correlation factors can be partially cancelled out in data analyses, the difference between these two factors in the low relative momentum region is so large that the distortion on the analysed results of two-pion interferometry from multi-pion interference becomes a serious problem when the pion source has a small radius and the pion multiplicity of event is high. The distributions of multi-pion correlation factor C-barn-2(q) can sensitively reflect the multi-pion correlation effects in the events. The analyses of multi-pion correlation factor for two Bevalac streamer chamber data samples of 2.1 A GeV Ne + Pb and 1.8 A GeV Ar + Pb collisions show that the multi-pion correlation effect in the former data sample is greater than that in the latter