A Leptophobic Z' And Dark Matter From Grand Unification
  We explore the phenomenology of Grand Unified Models based on the E_6 group,
focusing on the Z' with suppressed couplings to leptons that can appear in such
models. We find that this Z' can accommodate the W+dijets anomaly reported by
the CDF collaboration. Furthermore, a viable dark matter candidate in the form
of a right-handed sneutrino is also present within the fundamental
27-dimensional representation of E_6. Through its sizable couplings to the Z',
the dark matter is predicted to possess an elastic scattering cross section
with neutrons which can generate the signals reported by the CoGeNT and
DAMA/LIBRA collaborations. To avoid being overproduced in the early universe,
the dark matter must annihilate to leptons through the exchange of charged or
neutral fermions which appear in the 27 of E_6, providing an excellent fit to
the gamma ray spectrum observed from the Galactic Center by the Fermi Gamma Ray
Space Telescope.
