CENTRAL COLLISIONS OF 4.5 GEV C PER NUCLEON O-16 AND SI-28 NUCLEI IN NUCLEAR-EMULSION/

Central collisions of O-16 and Si-28 nuclei with heavy (AgBr) nuclei i n nuclear emulsion at 4.5 GeV/c per nucleon are selected and investiga ted under several selecting criteria. Central cross sections and avera ge number of interacting protons from both projectile acid target nucl ei, multiplicity distributions of shower particles and dispersions are discussed in the framework of the Glauber model. The multiplicities o f produced charged secondaries are studied according to the nucleon-nu cleus superposition model. The multiplicity distributions and mean val ues of grey particles are also investigated via a parameter free model whose input information is the distribution of grey particles produce d in proton induced reactions. It is shown that the selection criterio n of central collisions based only on the small total charge of stripp ing particles is too weak. The selection criteria based on the high mu ltiplicity of total secondary charged particles, the high degree of ta rget destruction and the large number of interacting protons augmented by the small total charge of stripping particles provide satisfactory agreement with the theoretical calculations.