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We discuss a novel mechanism for segregation of baryons and antibaryons 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 (A0) 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 antibaryons 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. [ABSTRACT FROM AUTHOR]

We study resonant gravitino production in the early Universe in the presence of SUSY flat directions whose large vacuum expectation values (VEVs) break some but not all gauge symmetries. We find that for a large region of parameter space, the gravitino abundance is several orders of magnitude larger than the cosmological upper bound. Since flat directions with large VEVs are generically expected in super-symmetric theories, this result further exacerbates the gravitino problem. [ABSTRACT FROM AUTHOR]

In this paper, we explore the possibility of spontaneous CP violation in the scattering of quarks and antiquarks from QCD Z(3) domain walls. The CP violation here arises from the nontrivial profile of the background gauge field (A0) between different Z(3) vacua. We calculate the spatial variation of A0 across the Z(3) interface from the profile of the Polyakov loop L(x) for the Z(3) interface and calculate the reflection of quarks and antiquarks using the Dirac equation. This spontaneous CP violation has interesting consequences for the relativistic heavy-ion collision experiments, such as baryon enhancement at high PT. It also acts as a source of additional J/&psgr; suppression. We also discuss its implications for the early Universe. [ABSTRACT FROM AUTHOR]