  Supersymmetric radiative neutrino mass models have often two dark matter
candidates. One is the usual lightest neutralino with odd R parity and the
other is a new neutral particle whose stability is guaranteed by a discrete
symmetry that forbids tree-level neutrino Yukawa couplings. If their relic
abundance is comparable, dark matter phenomenology can be largely different
from the minimal supersymmetric standard model (MSSM). We study this in a
supersymmetric radiative neutrino mass model with the conserved R parity and a
$Z_2$ symmetry weakly broken by the anomaly effect. The second dark matter with
odd parity of this new $Z_2$ is metastable and decays to the neutralino dark
matter. Charged particles and photons associated to this decay can cause the
deviation from the expected background of the cosmic rays. Direct search of the
neutralino dark matter is also expected to show different features from the
MSSM since the relic abundance is not composed of the neutralino dark matter
only. We discuss the nature of dark matter in this model by analyzing these
signals quantitatively.
