Nucleosynthesis in slowly evolving Cosmologies

TL;DR

This paper investigates nucleosynthesis in a universe with a linearly evolving scale factor, showing it can produce observed helium and metallicity levels through enhanced reaction rates due to high lepton density.

Contribution

It demonstrates that a linearly evolving cosmology can account for observed primordial element abundances and metallicity, offering an alternative to standard cosmological models.

Findings

Achieves adequate $^4He$ production consistent with observations.

Produces metallicity levels close to those in metal-poor stars.

Shows enhanced nucleosynthesis rates due to Coulomb screening effects.

Abstract

We explore aspects of Cosmological Nucleosynthesis in an FRW universe in which the scale factor evolves linearly with time: $a(t) \sim t$. A high Lepton number density during the period when significant nucleosynthesis takes place would lead to a dominant screening of the Coulomb potential of colliding nucleii. This would lead to a significant enhancement of nucleosynthesis rates. We demonstrate how adequate amount of $^4He$ and a collataral metallicity, close to the lowest metallicity observed in metal poor Pop II stars and clouds, can be produced with such an evolution.