FEW-BODY ASPECTS OF BORROMEAN HALO NUCLEI

Nuclei that exhibit pronounced halo structures are currently being exp lored in secondary beam experiments. Although Li-11 is the most famous example of a system with a halo of two loosely bound valence neutrons , He-6 shares many of the same properties. Both are what we refer to a s Borromean, i.e. while they are bound (only one bound state) they hav e, considered as three-body systems, no bound states in the binary sub systems. We argue that a three-body description is the natural one for central properties of such exotic loosely bound nuclei. Using He-6 as a benchmark system, we give a discussion of characteristic features b y comparing recent calculations and experiments.