Dark matter in SM4 and its implications in LFV decays

Abstract

The exact nature of dark matter is still a mystery to date. We consider a simple model in which standard model with three generation can be extended by one additional fourth family. The fourth generation neutrino ν4 is assumed to be heavy and stable which plays the role of dark matter. Using the constraint from relic density, the mass of the fourth neutrino is found to be (55–72)GeV. Next we study the implications of this model in various lepton flavor violating decays such as li →l jγ and li →lj lj lj.