Study of events in absence of target/projectile fragments in interactions of nuclei with emulsion at 4.5 and

This work is devoted to study two types of events. Type (a): events with no target fragments, the incident nucleus is dissociated in emulsion accompanied with the pions. Type (b): events with no projectile fragments, total break-up of the two colliding nuclei into relatively small fragments. Case of central collisions. The main characteristics of these reactions, that is multiplicity distributions of projectile and target fragments have been studied and compared for interactions of 4He, 12C, 16O, 22Ne and 28Si nuclei with emulsion at almost same momentum. The dependence of the mean multiplicity of different PFs on the projectile mass is investigated. Also the percentage of occurrence of these two events for different projectiles are analyzed.