Pionization at AGS and SPS energies ― degree of coherence and its target excitation dependence

Abstract

The target excitation dependence of the higher order cumulant correlation of pions is studied in the present work in the framework of void probability scaling. The data set of pions produced for 16O–AgBr interactions at 2.1 AGeV and 32S–AgBr interactions at 200 AGeV was divided into three sets depending upon the number of grey tracks ng. The different sets of ng correspond to different degrees of target excitation. Analysis was carried out for each set in different pseudorapidity intervals. For the lower projectile energy the void probability scaling is observed only for low target excitation for all pseudorapidity intervals. For the comparatively higher projectile energy, scaling is observed for all pseudorapidity intervals and all target excitation. In other words, for higher projectile energy, scaling is almost independent of the target excitation. The results are interpreted from the point of view of the two source model of particle production.