The scattering of composite nuclei is a very challenging quantum-mechanical many-body problem which, in most cases, is not exactly solvable. Thus, in most cases, one has to resort to approximations in order to reduce the problem to a tractable form. These approximations are usually tailored to specific types of reactions. In particular, in the case of reactions induced by weakly-bound nuclei, the effect of the breakup of the projectile must be somehow incorporated in the theoretical description.
The seminar is organized in two parts. In the first part, I will present some recent achievements in ab-initio and few-body models for nuclear reactions. Then, I will highlight some limitations of inert-core few-body methods and will present some extensions of these methods aimed at incorporating some core degrees of freedom ("core excitations"). The relevance of these core excitation mechanisms will be illustrated for several 11Be-induced reactions.
The second part will be devoted to the problem of the description of fusion reactions induced by weakly-bound nuclei. I will present a recently proposed method aimed at explaining the experimentally observed complete fusion suppression for these nuclei and its connection with the incomplete fusion and breakup mechanisms. The method will be illustrated with the 6,7Li+209Bi fusion measured by Dasgupta and collaborators.