Composite strongly interacting dark matter
  It has been suggested that cold dark matter (CDM) has difficulties in
explaining tentative evidence for noncuspy halo profiles in small galaxies, and
the low velocity dispersions observed in the largest Milky Way satellites ("too
big to fail" problem). Strongly self-interacting dark matter has been noted as
a robust solution to these problems. The elastic cross sections required are
much larger than predicted by generic CDM models, but could naturally be of the
right size if dark matter is composite. We explore in a general way the
constraints on models where strongly interacting CDM is in the form of dark
"atoms" or "molecules," or bound states of a confining gauge interaction
("hadrons"). These constraints include considerations of relic density, direct
detection, big bang nucleosynthesis, the cosmic microwave background, and LHC
data.
