  Momentum distributions of particles from nuclear break-up of fast three-body
halos are calculated for polarized beam and outgoing fragments. These momentum
distributions are combined in observable quantities which emphasize the
two-body correlations in the initial three-body structure as well as in the
final two-body system. Applying the formalism to 11Li we find a sensitive
dependence on the p-wave content and on the position of the p-resonances in
10Li. Polarization experiments are then a new tool to study correlations in
nuclear halos.
