New gamma ray signal from gravitationally boosted neutralinos at the
  galactic center
  We discuss on the possibility that colliding dark matter particles in the
form of neutralinos may be gravitationally boosted near the super-massive black
hole at the galactic center so that they can have enough collision energy to
annihilate into a stau pair. Since in some phenomenologically favored
supersymmetric models the mass splitting between the neutralino and the
lightest stau, one of the two scalar superpartners of the tau lepton, is a few
GeVs, this channel may be allowed. In addition, staus can only decay into a tau
lepton and another neutralino. We calculate the gamma-ray spectrum and flux
generated by the tau pair discussing the observability of the obtained
features.
