Production of lithium, beryllium, and boron from baryon inhomogeneous primordial nucleosynthesis

We investigate the possibility that inhomogeneous nucleosynthesis may eventually be used to explain the abundances of ⁶Li, ⁹Be, and B in Population II stars. The present work differs from previous studies in that we have used a more extensive reaction network. It is demonstrated that in the simplest scenario the abundances of the light elements with A < 7 constrain the separation of inhomogeneities to sufficiently small scales that the model is indistinguishable from homogeneous nucleosynthesis and that the abundances of ⁶Li, ⁹Be, and B are then below observations by several orders of magnitude. This conclusion does not depend on the ⁷Li constraint. We also examine alternative scenarios which involve a post-nucleosynthesis reprocessing of the light elements to reproduce the observed abundances of Li and B, while allowing for a somewhat higher baryon density (still well below the cosmological critical density). Future B/H measurements may be able to exclude even this exotic scenario and further restrict primordial nucleosynthesis to approach the homogeneous model conclusions.