Nucleosynthesis in a universe with a linearly evolving scale factor

Primordial nucleosynthesis is regarded as a success story of the standard b ig bang (SBB) cosmology. In this article nucleosynthesis is explored in mod els in which the cosmological scale factor R(t) increases linearly with tim e. This relationship of R(t) and t continues from the period when nucleosyn thesis begins until the present time. It turns out that weak interactions r emain in thermal equilibrium upto temperatures which are two orders of magn itude lower than the corresponding (weak interaction decoupling) temperatur es in SBB. Inverse beta decay of the proton can ensure adequate production of helium while producing primordial metallicity much higher than that prod uced in SBB. Attractive features of such models are the absence of the hori zon, flatness and age problems as well consistency with classical cosmologi cal tests.