Dynamical Fragment Production as a Mode of Energy Dissipation in Heavy-Ion Reactions

Based on measured correlations between experimental observables in the ${}^{209}\mathrm{Bi}{+}^{136}\mathrm{Xe}$ reaction at $E/A=28\mathrm{MeV}$, it is shown that multiple intermediate-mass fragment (IMF) production is a dynamical process driven by the energy of relative motion of projectilelike and targetlike fragments. This kinetic energy is converted into thermal energy of the system, until a certain “saturation” value of approximately 3 MeV/nucleon is reached. From this point on, this “conventional” dissipation mechanism is replaced by dynamical IMF production, constituting a new mode of energy dissipation.