Dark Quark Nuggets
  "Dark quark nuggets", a lump of dark quark matter, can be produced in the
early universe for a wide range of confining gauge theories and serve as a
macroscopic dark matter candidate. The two necessary conditions, a nonzero dark
baryon number asymmetry and a first-order phase transition, can be easily
satisfied for many asymmetric dark matter models and QCD-like gauge theories
with a few massless flavors. For confinement scales from 10 keV to 100 TeV,
these dark quark nuggets with a huge dark baryon number have their masses vary
from $10^{23}~\mathrm{g}$ to $10^{-7}~\mathrm{g}$ and their radii from
$10^{8}~\mathrm{cm}$ to $10^{-15}~\mathrm{cm}$. Such macroscopic dark matter
candidates can be searched for by a broad scope of experiments and even new
detection strategies. Specifically, we have found that the gravitational
microlensing experiments can probe heavier dark quark nuggets or smaller
confinement scales around 10 keV; collision of dark quark nuggets can generate
detectable and transient electromagnetic radiation signals; the stochastic
gravitational wave signals from the first order phase transition can be probed
by the pulsar timing array observations and other space-based interferometry
experiments; the approximately massless dark mesons can behave as dark
radiation to be tested by the next-generation CMB experiments; the free dark
baryons, as a subcomponent of dark matter, can have direct detection signals
for a sufficiently strong interaction strength with the visible sector.
