Signal from sterile neutrino dark matter in extra U(1) model at direct detection experiment

We examine the possibility that direct dark matter detection experiments find decay products from sterile neutrino dark mater in U_{(1) B - L} and U(_1)R models. This is possible if the sterile neutrino interacts with a light gauge boson, and decays into a neutrino and the light gauge boson with a certain lifetime. This decay produces energetic neutrinos scattering off nuclei with a large enough recoil energy in direct dark matter detection experiments. We stress that direct dark matter detection experiments can explore not only WIMP but also sterile neutrino dark matter.