The correlation strength in pion interferometry

The role of the parameter in pion interferometry, thecorrelation strength, is investigated. The relations between the extracted values for and the radii are emphasized and illustrated by a compilation of published data. It is shown that radii from interferometry measurements can often not be interpreted independently from . The validity of quantitative radius estimates based on the freeze-out picture is discussed. From pion interferometry data at target rapidity in 200A GeV¹⁶O+Au collisions an effective rescattering cross section for soft pions of 11 mb is extracted.