Bindings in the dark : bound states in dark matter phenomenology

It is almost a century now since data implying the presence of nonluminous matter in the Universe surfaced: in 1932 Oort [1] observed that the number of stars near the sun was 30´50% less than the number necessary to explain their velocities; then, in 1933, Zwicky [2] pointed out that the velocity dispersion of galaxies in the Coma cluster required 10 to 100 times more mass than the one accounted for the luminous galaxies themselves. The same Zwicky called this unseen matter dunkle materie (dark matter). These observations were practically ignored for almost four decades until a large number of new evidences corroborating the claim of Oort and Zwicky emerged. Nowadays evidences advocating the existence of Dark Matter (DM) range from the galactic scale, where DM is needed to explain the observed stellar dynamics, to cosmological scales, DM being one of the pillars of the ΛCDM model. However, despite its central role, the nature of the DM remains unknown. This ignorance, which mostly stems from our inability to detect nongravitational interactions between dark and baryonic matter, together with the fact that DM is one of the few phenomenological flaws of the Standard Model (SM) has driven a huge activity in the theoretical community.1 However, if the lack of information about the DM properties makes quite easy is to come up with plausible theoretical solutions it also makes very hard to proof or disproof them. Thus it is crucial to keep pushing the experimental frontiers in parallel with the theoretical efforts. In the following we summarize the (few) experimental informations we have about the DM, and the experimental endeavors that the community is undergoing in the attempt to unveil some of its key features. [...]