Four-body distorted-wave theory for halo excitations in peripheral fragmentation reactions

A microscopic approach to breakup into the low-energy continuum of Borromea n two-neutron-halo nuclei is developed by quantum mechanically taking into account both Coulomb and nuclear dissociation. The crucial role of both ela stic and inelastic fragmentation is demonstrated for He-6 breakup on C and Ph targets at intermediate energies in kinematically complete experiments. For the first time, recent GSI experimental data are analyzed quantitativel y, and a rich and complex interplay of reaction mechanisms and low-lying ha lo excitations is revealed. (C) 2001 MAIK "Nauka/Interperiodica".