  We propose a new mechanism to generate the neutrino Majorana mass in
TeV-scale gravity models. The black hole violates all non-gauged symmetries and
can become the origin of lepton number violating processes. The fluctuation of
higher-dimensional spacetime can result in the production of a black hole,
which emits 2 neutrinos. If neutrinos are Majorana particles, this process is
equivalent to the free propagation of a neutrino with the insertion of the
black hole. From this fact, we derive the neutrino Majorana mass. The result is
completely consistent with the recently observed evidence of neutrinoless
double beta decay. And the obtained neutrino Majorana mass satisfies the
constraint from the density of the neutrino dark matter, which affects the
cosmic structure formation. Furthermore, we can explain the ultrahigh energy
cosmic rays by the Z-burst scenario with it.
