Stochastic Isocurvature Baryon Fluctuations, Baryon Diffusion, and Primordial Nucleosynthesis
Abstract
We examine effects on primordial nucleosynthesis from a truly random, onedimensional spatial distribution in the baryontophoton ratio (η). We generate stochastic fluctuation spectra characterized by different spectral indices and rms fluctuation amplitudes. For the first time we explicitly calculate the effects of baryon diffusion on the nucleosynthesis yields of such stochastic fluctuations. We also consider the collapse instability of large mass scale inhomogeneities. Our results are generally applicable to any primordial mechanism producing fluctuations in η which can be characterized by a spectral index. In particular, these results apply to primordial isocurvature baryon fluctuation (PIB) models. The amplitudes of fluctuations that are scaleinvariant in baryon density are found to be severely constrained by primordial nucleosynthesis. However, when the η distribution is characterized by decreasing fluctuation amplitudes with increasing length scale, surprisingly large fluctuation amplitudes on the baryon diffusion scale are allowed.
 Publication:

The Astrophysical Journal
 Pub Date:
 April 1997
 DOI:
 10.1086/303858
 arXiv:
 arXiv:astroph/9606011
 Bibcode:
 1997ApJ...479...31K
 Keywords:

 Cosmology: Theory;
 Cosmology: Dark Matter;
 Cosmology: Early Universe;
 Cosmology: LargeScale Structure of Universe;
 Nuclear Reactions;
 Nucleosynthesis;
 Abundances;
 Astrophysics
 EPrint:
 LaTeX, 11 pages and 4 figures, aas2pp4.sty