NUCLEOSYNTHESIS IN A UNIVERSE WITH A LINEARLY EVOLVING SCALE FACTOR

Abstract

Primordial nucleosynthesis is regarded as a success story of the standard big bang (SBB) cosmology. In this article nucleosynthesis is explored in models in which the cosmological scale factor R(t) increases linearly with time. This relationship of R(t) and t continues from the period when nucleosynthesis begins until the present time. It turns out that weak interactions remain in thermal equilibrium upto temperatures which are two orders of magnitude lower than the corresponding (weak interaction decoupling) temperatures in SBB. Inverse beta decay of the proton can ensure adequate production of helium while producing primordial metallicity much higher than that produced in SBB. Attractive features of such models are the absence of the horizon, flatness and age problems as well consistency with classical cosmological tests.