Constraint on Heavy Element Production in Inhomogeneous Big-Bang Nucleosynthesis from the Light Element Observations

Abstract

We investigate the observational constraints on the inhomogeneous big-bang nucleosynthesis that Matsuura et al [1] suggested the possibility of the heavy element production beyond 7 Li in the early universe. From the observational constraints on light elements of 4 He and D, possible regions are found on the plane of the volume fraction of the high density region against the ratio between highand low-density regions. In these allowed regions, we have confirmed that the heavy elements beyond Ni can be produced appreciably, where p-and/or r-process elements are produced well simultaneously.

Big-bang nucleosynthesis in comparison with observed helium and deuterium abundances: Possibility of a nonstandard model

“…As a consequence, the average value of 7 Li between the high and the low density regions becomes lower than the predicted value in SBBN [46].…”

7Li Production in Inhomogeneous Big-Bang Nucleosynthesis

“…In recent studies, heavy elements, such as 56 Ni, 92 Mo, 96 Ru, can be synthesized in a high-density region [8]. On the other hand, it has been reported that the Li/H value can be lower than that of the SBBN [9]. In this study, we compare the Li value with the observation in the IBBN model.…”

“…In our study, we adopt the two-zone model where the early universe has a high-and low-baryon density regions(e.g. [8,9]). Here we assume the baryon fluctuation is isothermal [4] The diffusion effect of nuclei is ignored because the time scale of diffusion is longer than that of the cosmic expansion [5].…”

Production of Li and B in Inhomogeneous Big-Bang Nucleosynthesis

“…We calculate the nucleosynthesis in high and low-density regions where the nucleosynthesis code is the same as the previous study [5,6] which include 464 nuclei from neutron to 94 Kr. The reaction rates for mass number A < 16 are updated to those of Descouvemont el al.…”

“…If there are a high-density region with η > 10 −5 , the heavy elements such as 56 Ni and 90 Zr can be synthesized [5,6]. In this study, we focus on the abundances of Li, Be, and B in IBBN model.…”