Compact Dark Matter Objects via $N$ Dark Sectors
  We propose a novel class of compact dark matter objects in theories where the
dark matter consists of multiple sectors. We call these objects $N$-MACHOs. In
such theories neither the existence of dark matter species nor their extremely
weak coupling to the observable sector represent additional hypotheses but
instead are imposed by the solution to the Hierarchy Problem and unitarity. The
crucial point is that particles from the same sector have non-trivial
interactions but interact only gravitationally otherwise. As a consequence, the
pressure that counteracts the gravitational collapse is reduced while the
gravitational force remains the same. This results in collapsed structures much
lighter and smaller as compared to the ordinary single-sector case. We apply
this phenomenon to a dark matter theory that consists of $N$ dilute copies of
the Standard Model. The solutions do not rely on an exotic stabilization
mechanism, but rather use the same well-understood properties as known stellar
structures. This framework also gives rise to new microscopic superheavy
structures, for example with mass $10^8\,$g and size $10^{-13}\,$cm. By
confronting the resulting objects with observational constraints, we find that,
due to a huge suppression factor entering the mass spectrum, these objects
evade the strongest constrained region of the parameter space. Finally, we
discuss possible formation scenarios of $N$-MACHOs. We argue that, due to the
efficient dissipation of energy on small scales, high-density regions such as
ultra-compact mini-halos could serve as formation sites of $N$-MACHOs.
