Study of intermediate velocity products in the Ar plus Ni collisions between 52 and 95 A.MeV

Intermediate velocity products in Ar + Ni collisions from 52 to 95 A.MeV are studied in an experiment performed at the GANIL facility with the 4 pi multidetector INDRA. It is shown that these emissions cannot be explained by statistical decays of the quasi-projectile and the quasi-target in complete equilibrium. Three methods are used to isolate and characterize intermediate velocity products. The total mass of these products increases with the violence of the collision and reaches a large fraction of the system mass in mid-central collisions. This mass is found independent of the incident energy, but strongly dependent on the geometry of the collision. Finally it is shown that the kinematical characteristics of intermediate velocity products are weakly dependent on the experimental impact parameter, but strongly dependent on the incident energy. The observed trends are consistent with a participant-spectator-like scenario or with neck emissions and/or breakup. (C) 2000 Elsevier Science B.V. All rights reserved.