Mass scaling of reaction mechanisms in intermediate energy heavy ion collisions

Reaction mechanisms have been studied for two nearly symmetrical systems of different total mass, between 25 and 74 A MeV. It is shown that collisions are mostly binary whatever the system mass and the bombarding energy. From the slowing-down of the partners, it is possible to establish the continuous evolution from quasielastic to (completely) damped collisions. It turns out that results are independent of the total system mass if involved energies are expressed in A MeV. The occurrence of mid-rapidity emission is also considered and may be used to establish a link between mechanisms observed at low and high bombarding energy. Part of it corresponds to a fast decay of outgoing partners.