Scattering of massive W bosons into gravitinos and tree unitarity in
  broken supergravity
  The WW scattering into gravitino and gaugino is here investigated in the
broken phase, by using both gauge and mass eigenstates. Differently from what
is obtained for unbroken gauge symmetry, we find in the scattering amplitudes
new structures, which can lead to violation of unitarity above a certain scale.
This happens because, in the annihilation diagram, the longitudinal degrees of
freedom in the propagator of the gauge bosons disappear from the amplitude, by
virtue of the SUGRA vertex. We show that the longitudinal polarizations of the
on-shell W become strongly interacting in the high energy limit, and that the
inclusion of diagrams with off-shell scalars of the MSSM does not cancel the
divergences.
