What cosmological model for the universe took place approximately 13.8 Billion years ago and is generally understood to be nucleosynthesis in stars followed by mass ejection?
Primordial nuclide In geochemistry, geophysics and geonuclear physics, primordial nuclides, also known as primordial isotopes, are nuclides found on Earth that have existed in their current form since before Earth was formed. Primordial nuclides were present in the interstellar medium from which the solar system was formed, and were formed in the Big Bang, by nucleosynthesis in stars and supernovae followed by mass ejection, by cosmic ray spallation, and potentially from other processes. They are the stable nuclides plus the long-lived fraction of radionuclides surviving in the primordial solar nebula through planet accretion until the present. Only 286 such nuclides are known.
Light dark matter In astronomy and cosmology, light dark matter are dark matter weakly interacting massive particle (WIMP) candidates with masses less than 1 GeV. These particles are heavier than warm dark matter and hot dark matter, but are lighter than the traditional forms of cold dark matter. The Lee-Weinberg bound limits the mass of the favored dark matter candidate, WIMPs, that interact via the weak interaction to formula_1 GeV. This bound arises as follows. The lower the mass of WIMPs is, the lower the annihilation cross section, which is of the order formula_2, where "m" is the WIMP mass and "M" the mass of the Z-boson. This means that low mass WIMPs, which would be abundantly produced in the early universe, freeze out (i.e. stop interacting) much earlier and thus at a higher temperature, than higher mass WIMPs. This leads to a higher relic WIMP density. If the mass is lower than formula_3 GeV the WIMP relic density would overclose the universe.