Dissipative fragmentation and deep-inelastic scattering at 20 MeV/a

Correlations of two coincident alpha-particles and deep-inelastic fragments (Li-Mg) coincident with alpha-particles were measured at small and large relative angles after bombarding 197Au with 20Ne at 20 MeV/nucleon in order to isolate nontrivial mechanisms contributions from the decay of projectile-like fragments, target-like fragments, or both, were determined and subtracted from the experimental angular correlations. The remaining parts in both correlations (alpha-alpha and deep-inelastic-alpha) are compared to the dynamical model for projectile break-up by Moehring et al. In this model 20Ne is considered a bound system of 5 alpha particles which individually interact with the target via a folding potential and frictional forces. In addition to a good reproduction of the inclusive cross sections of quasi-elastic and deep-inelastic events, the model reproduces the observed correlations quantitatively. According to the model analysis, the alpha-alpha correlations are described as a dissipative fragmentation of the whole projectile or parts of it. The alpha-fragment correlations can be explained as a release of an alpha-particle at an early phase of the reaction while the projectile remnant follows an orbiting trajectory