The Scalar Hexaquark $uuddss$: a Candidate to Dark Matter?
  It is conventionally argued that Dark Matter (DM) has a non-baryonic nature,
but if we assume that DM was frozen out before primordial nucleosynthesis and
could not significantly impact primordial abundances this argument may be
evaded. Then a hypothetical $SU(3)$ flavor-singlet, highly symmetric, deeply
bound neutral scalar hexaquark $\mathrm{S}=uuddss$, which due to its features
has escaped from experimental detection so far, may be considered as a
candidate for a baryonic DM. In the present work we calculate the mass and
coupling constant of the scalar six-quark particle $\mathrm{S}$ by means of the
QCD sum rule method. Our predictions for its mass are $
m_{S}=1180_{-26}^{+40}~\mathrm{MeV}$ ($m_s=95~\mathrm{MeV}$) and $ \widetilde
{m}_{S}=1239_{-28}^{+42}~\mathrm{MeV}$ ($m_s=128~\mathrm{MeV}$). Although these
values of mass would produce thermally the cosmological DM abundance, existence
of this state may contradict to stability of the oxygen nuclei, which requires
further thorough analysis.
