  Pure singlets are typically disfavored as dark matter candidates, since they
generically have a thermal relic abundance larger than the observed value. In
this paper, we propose a new dark matter mechanism called "assimilation", which
takes advantage of the baryon asymmetry of the universe to generate the correct
relic abundance of singlet dark matter. Through assimilation, dark matter
itself is efficiently destroyed, but dark matter number is stored in new
quasi-stable heavy states which carry the baryon asymmetry. The subsequent
annihilation and late-time decay of these heavy states yields (symmetric) dark
matter as well as (asymmetric) standard model baryons. We study in detail the
case of pure bino dark matter by augmenting the minimal supersymmetric standard
model with vector-like chiral multiplets. In the parameter range where this
mechanism is effective, the LHC can discover long-lived charged particles which
were responsible for assimilating dark matter.
