SOURCE DENSITY DISTRIBUTION AND INTENSITY INTERFEROMETRY IN HIGH-ENERGY HEAVY-ION COLLISIONS

The fitted spatial parameter from intensity interferometry relates to an average radius (r) of the particle-emitting source. The mean-square radius <r2> of the source can be estimated by the small relative momentum correlation function. More detailed information about the source density distribution can be inferred from the value of k = <r2>/<r>2. A study of central collisions of 1.8 A GeV Ar + Pb at the Bevalac streamer chamber shows that the data are consistent with an a priori Gaussian model for the density distribution at the present level of experimental accuracy. The average radius of the pion source in the reaction is deduced, and a possible picture to describe the expanding pion source is presented.