Reviving quark nuggets as a candidate for dark matter
  We discuss a novel mechanism for segregation of baryons and anti-baryons in
the quark-gluon plasma phase which can lead to formation of quark and antiquark
nuggets in the early universe, irrespective of the order of the quark-hadron
phase transition. This happens due to CP violating scattering of quarks and
antiquarks from moving $Z(3)$ domain walls. CP violation here is spontaneous in
nature and arises from the nontrivial profile of the background gauge field
($A_{0}$ ) between different $Z(3)$ vacua. We study the effect of this
spontaneous CP violation on the baryon transport across the collapsing large
$Z(3)$ domain walls (which can arise in the context of certain low energy scale
inflationary models). Our results show that this CP violation can lead to large
concentrations of baryons and anti-baryons in the early universe. The quark and
antiquark nuggets, formed by this alternate mechanism, can provide a viable
dark matter candidate within standard model without violating any observational
constraints.
