Composite Scalar Dark Matter
  We show that the dark matter (DM) could be a light composite scalar $\eta$,
emerging from a TeV-scale strongly-coupled sector as a pseudo Nambu-Goldstone
boson (pNGB). Such state arises naturally in scenarios where the Higgs is also
a composite pNGB, as in $O(6)/O(5)$ models, which are particularly predictive,
since the low-energy interactions of $\eta$ are determined by symmetry
considerations. We identify the region of parameters where $\eta$ has the
required DM relic density, satisfying at the same time the constraints from
Higgs searches at the LHC, as well as DM direct searches. Compositeness, in
addition to justify the lightness of the scalars, can enhance the DM scattering
rates and lead to an excellent discovery prospect for the near future. For a
Higgs mass $m_h\simeq 125$ GeV and a pNGB characteristic scale $f \lesssim 1$
TeV, we find that the DM mass is either $m_\eta \simeq 50-70$ GeV, with DM
annihilations driven by the Higgs resonance, or in the range 100-500 GeV, where
the DM derivative interaction with the Higgs becomes dominant. In the former
case the invisible Higgs decay to two DM particles could weaken the LHC Higgs
signal.
