Incomplete deep inelastic processes in medium mass heavy ion collision at 18 and 24 MeV/u

Experimental evidences for an impact parameter dependence of preequilibrium processes in ¹⁰⁰Mo+¹⁰⁰Mo at 18.67 MeV/u, 23.75 MeV/u and in ¹²⁰Sn+¹²⁰Sn at 18.34 MeV/u are presented. An incomplete deep inelastic mechanism is proposed. Such a process explains the deviations observed at these incident energies in σ_z²−TKEL/1_g (for two body) and P₃/(P₂+P₃)−TKEL (for three body) systematics. Model predictions for the preequilibrium emitted nucleons and the corresponding excitation energy per nucleon which remains in the dinuclear system are compared with the experimental data.