Production of the light elements in primordial nucleosynthesis

Abstract

The abundances of the light nuclides Be9, B10 and B11 are reexamined in the contexts of the standard model of primodial nucleosynthesis, in which the density of the universe is assumed to be uniform, and of the nonuniform density model, in which density fluctuations are allowed. In these calculations, two reactions not usually included in primodial nucleosynthesis models have been included: Li7(H3,n)Be9 and Be9(H3,n)B11. Wide ranges of the parameters associated with the nonuniform density model were spanned; the resuls show that considerably higher abundances of Be9, B10, and B11 are produced in that model than in the standard model for most values of the parameters associated with the former model. Furthermore, a study of the galatic chemical evolution of those nuclides which considers all their production mechanisms shows that their abundances depend strongly on those mechanisms. However, measurement of the time dependence of their abundances, together with that of Li7, might resolve the present controversy surrounding the Li7 abundance, and provide a test of primodial nucleosynthesis models as well. In our study of the galatic chemical evolution of Be9, B10, and B11 since the time of primodial nucleosynthesis, explicit note is mode of the factors which have the largest uncertainties. Although the allowed rages are found to be large, observational limits on Be9, B10, and B11 are approaching the level needed to provide a definitive test of the predictions of the two primodial nucleosynthesis models.