Nucleosynthesis in a simmering univeerse

Abstract

Primordial nucleosynthesis is considered a success story of the standard big bang (SBB) cosmology. The cosmological and elementary particle physics parameters are believed to be severely constrained by the requirement of correct abundances of light elements. We explore nucleosynthesis in a class of models very different from SBB. In these models the cosmological scale factor increases linearly with time right through the period during which nucleosynthesis occurs till the present. 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) temperature in SBB. Inverse beta decay of the proton can ensure adequate production of several light elements while producing primordial metalicity much higher than that produced in SBB. Other attractive features of these models are the absence of the horizon, flatness and the age problems and consistency with classical cosmological tests.