Composite Dark Matter and Puzzles of Dark Matter Searches

International audiencePositive results of dark matter searches in DAMA/NaI and DAMA/LIBRA experiments, being put together with the results of other groups, can imply nontrivial particle physics solutions for cosmological dark matter. Stable particles with charge -2, bound with primordial helium in O-helium "atoms" (OHe), represent a specific warmer than cold nuclear-interacting form of dark matter. Slowed down in the terrestrial matter, OHe is elusive for direct methods of underground dark matter detection used in cryogenic experiments. However the radiative capture of OHe by Na and I nuclei can lead to annual variations of energy release in the energy interval of 2-5 keV in DAMA/NaI and DAMA/LIBRA experiments