Composite dark matter from stable charged constituents
  Heavy stable charged particles can exist, hidden from us in bound atomlike states. Models with new stable charged leptons and quarks give rise to realistic composite dark matter scenarios. Significant or even dominant component of O-helium (atomlike system of He4 nucleus and heavy -2 charged particle) is inevitable feature of such scenarios. Possible O-helium explanation for the positron excess in the galactic bulge and for the controversy between the positive results of DAMA and negative results of other experiments is proposed. 
Maxim Yu. Khlopov