Clustering in light nuclei and their effects on fusion and pre - Equilibrium processes.

The study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is important to study the pre-formation of α-clusters in α-conjugate nuclei and the dynamical condensation of clusters during nuclear reactions [1-5]. The NUCL-EX collaboration has recently initiated an experimental campaign of exclusive measurements of fusion-evaporation reactions with light nuclei as interacting partners. In collisions involving light systems, the low expected multiplicity of fragments increases the probability of achieving a quasi-complete reconstruction of the event. In particular the formation and decay modes of an excited ²⁴Mg system have been studied through two different reactions, ¹²C (95 MeV)+ ¹²C and ¹⁴N (80.7 MeV)+ ¹⁰B, which have been used to produce fused systems with nearly the same mass and excitation energy (∼60 MeV). In particular, even the de-excitation of the Hoyle state in ¹²C have been studied, both in peripheral (projectiles de-excitation) and in central collisions (six α-particles channel). Moreover, a research campaign studying pre-equilibrium emission of light charged particles and cluster properties of light and medium-mass nuclei has been carried out. For this purpose, a comparative study of the three nuclear systems ¹⁸O+²⁸Si, ¹⁶O+³⁰Si and ¹⁹F+²⁷Al has been recently studied using the GARFIELD+RCo 4π setup [6]. The experimental data are compared with the predictions of simulated events generated with the statistical models (GEMINI⁺⁺ and HFl) and through dynamical models like Stochastic Mean Field (SMF) and Antisymmetrized Molecular Dynamics (AMD) and filtered with a software replica of our apparatus in order to take into account the experimental conditions.