Beta Decay and Nucleosynthesis

Abstract

We investigate the finite temperature and density effects on beta decay rate due to the change in electron mass through its interaction with the medium. The propagation of electrons and their interaction with the medium modifies the properties of electrons and affects the beta decay rate significantly. The modification in beta decay rate in various statistical conditions is related to the rate of nucleosynthesis in that background. The properties of other heavier leptons are also modified at higher temperatures, but they are not relevant for nucleosynthesis in the early universe. The detailed investigation of the chemical potential effect on the properties of leptons is also included in this thesis. We incorporate the chemical potential effects along with temperature on properties of leptons to compute precisely the beta decay and nucleosynthesis in stellar cores. Upon interpreting the data, it was found that the self-mass of a lepton in finite temperature and density affects the beta decay rate, which also affects the change in Helium abundance. High chemical potentials in a neutron star environment result in a higher self-mass. High temperatures in the early universe, give rise to a higher self-mass as well