Form Factor Dark Matter
  We present a dynamical alternative to inelastic dark matter as a way of
reconciling the modulating signal seen at DAMA with null results at other
direct detection experiments. The essential ingredient is a new form factor
which introduces momentum dependence in the interaction of dark matter with
nuclei. The role of the form factor is to suppress events at low momentum
transfer. We find that a form factor approach is most likely not viable in the
context of the standard halo model, however it is consistent with halo models
suggested by recent Via Lactea simulations. As an example of possible form
factors, we present a class of models where the necessary momentum dependence
arises from interference of GeV mass gauge bosons coupling the dark matter to
nuclei. At energies relevant for direct detection experiments these models
contain one or two additional parameters beyond the case of a standard WIMP.
