Bounds on Light Dark Matter

The nature of Dark Matter (DM) is one of the most intriguing questions of modern physics. Its resolution would have a profound impact on the development of particle physics beyond its Standard Model (SM). Although the possibility of having massive compact halo objects (MACHOs) as a dominant form of DM is still under debates (see recent discussion in [1] and references therein), it is widely believed that DM is made of non-baryonic particles. Yet the SM of elementary particles does not contain a viable DM particle candidate – massive, neutral and long-lived particle. Active neutrinos, which are both neutral and stable, form structures in a top-down fashion [2], and thus cannot produce observed large scale structure. Therefore, the DM particle hypothesis implies the extension of the SM. Thus, constraining properties of the DM, helps to distinguish between various DM candidates and may help to differentiate among different beyond the SM models (BSM). What is known about the properties of DM particles?