Effect of finite temperature β-decay on the r-process nucleosynthesis

The heaviest elements in nature are synthesized in the rapid neutron capture process (r-process). The r-process is believed to occur in hot, dense, and neutron-rich environments, such as ejecta from compact binary mergers and some types of core-collapse supernovae. The yield of the nucleosynthesis event sensitively depends on the balance of various kinds of nuclear reactions and decays— neutron capture, photodissociation, β-decay, fission, and more.

In a typical nuclear reaction network calculation that computes the evolution of the abundance of nuclei, nuclear reaction rates (e.g. neutron capture rates) are treated as temperature-dependent, on the other hand, β-decay rates are fixed. However, it has been pointed out that the temperature dependence of β-decay rates in stellar environments is not negligible.

Recently, β-decay rates were computed for nuclei with 20≦Z≦60 as functions of temperature and electron density of the environment. Calculations are based on the covariant energy density functional theory and the finite-temperature proton-neutron relativistic quasiparticle random-phase approximation (FT-PNRQRPA). In this talk, the results of the investigation into the effect of the finite-temperature β-decay rates on the r-process nucleosynthesis will be discussed.