Heavy sterile neutrino in dark matter searches

Sterile neutrinos are possible dark matter candidates. We examine here possible detection mechanisms, assuming that the neutrino has a mass of about 50 keV and couples to the ordinary neutrino. Even though this neutrino is quite heavy, it is non relativistic with a maximum kinetic energy of 0.1 eV. Thus new experimental techniques are required for its detection. We estimate the expected event rate in the following cases: i) Measure electron recoils in the case of materials with very low electron binding. ii) Low temperature crystal bolometers. iii) Spin induced atomic excitations at very low temperatures, leading to a characteristic photon spectrum. iv) Observation of resonances in antineutrino absorption by a nucleus undergoing electron capture. v) Neutrino induced electron events beyond the end point energy of beta decaying systems, e.g. in the tritium decay studied by KATRIN.