Hierarchically Acting Sterile Neutrinos

We propose that a hierarchical spectrum of sterile neutrinos (eV, keV, ${10}^{13-15}$ GeV) is considered to as the explanations for MiniBooNE and LSND oscillation anomalies, dark matter, and baryon asymmetry of the universe (BAU) respectively. The scenario can also realize the smallness of active neutrino masses by seesaw mechanism.