Abstract
I consider the synthesis of due to the decay of relic particles, such as gravitinos or moduli, after the epoch of big bang nucleosynthesis. The synthesized ratio may be compared to in metal-poor stars which, in the absence of stellar depletion of , yields significantly stronger constraints on relic particle densities than the usual consideration of overproduction of . Production of during such an era of nonthermal nucleosynthesis may also be regarded as a possible explanation for the relatively high ratios observed in metal-poor halo stars.
- Received 15 October 1999
DOI:https://doi.org/10.1103/PhysRevLett.84.3248
©2000 American Physical Society