Late-time neutron diffusion and nucleosynthesis in a post QCD inhomogeneous Ωb=1 universe

Although recent models concerning the cosmologial quark--hadron phase transition and the resulting primordial nucleosynthesis seem attractive in several respects, it could be argued that the high production of 7Li from such models render them of little interest, especially since low-density standard big bang calculations can adequately account for all of the primordial isotopes. However, a dynamic nucleosynthesis calculation taking into account the diffusion of matter, during the nucleosynthesis epoch, between the different density regions produced by the phase transition, has not yet been carried out. We investigate here the consequences of such a diffusion and identify a high-density, Ωb=1, universe which under specific conditions can reproduce the observed primordial isotopes including that of 7Li. We discuss how the low deterium abundance predicted by this early universe can help resolve the problem of deuterium depletion associated with standard galactic chemical evolution models. We further show that the amount of A>56 isotopes produced in this universe may help explain why second generation stars possess s-process elements in their stellar atmospheres. copyright 1989 Academic Press, Inc