New Observables in Break-up Reactions of Three-body Halos

Momentum distributions of particles from fast three-body halo fragmentation reactions with polarized beams and outgoing fragments are analyzed by use of the sudden approximation. The final state interaction between the two non-disturbed particles is considered. We first give a general and detailed description of the method. We introduce observable quantities that emphasize the two-body correlations in the initial three-body structure as well as in the final two-body system. Using neutron removal from 11Li as an example we investigate the dependence of the polarization observables on the properties of the low-lying resonances and virtual states of the 10Li subsystem. These observables are very sensitive to the l > 0-waves in the wave functions, and they provide detailed information on the resonance structure of the neutron-core subsystem.