  We investigate the parameter space of a supersymmetric model with an extended
U(1) gauge symmetry in which the RH sneutrino is a thermal dark matter
candidate. In this scenario, annihilation of RH sneutrinos proceeds mainly
through Higgs or Z' exchange. We find that sneutrinos in the mass range from
50GeV to more than 1 TeV can be consistent with both the WMAP limit and the
direct detection upper limits. Powerful constraints from new gauge boson
searches at the LHC as well as from $\Delta M_s$ are incorporated. Depending on
the choice of the U(1) charge, these scenarios will be further probe by direct
dark matter searches as well as by Higgs searches at the LHC.
