Impact of New beta-decay Half-lives on r-process Nucleosynthesis

TL;DR

This paper examines how newly measured beta-decay half-lives influence r-process nucleosynthesis, showing they increase certain isotope abundances and partially address previous underproduction issues in models.

Contribution

It introduces new experimental beta-decay rates into r-process models, revealing their impact on nucleosynthesis yields and timescales in a magnetohydrodynamic supernova environment.

Findings

Enhanced abundance of isotopes with A=110-120

Partial alleviation of underproduction of certain isotopes

New beta-decay rates influence r-process timescales

Abstract

We investigate the effects of newly measured beta-decay half-lives on r-process nucleosynthesis. These new rates were determined by recent experiments at the radioactive isotope beam factory facility in the RIKEN Nishina Center. We adopt an r-process nucleosynthesis environment based on a magnetohydrodynamic supernova explosion model that includes strong magnetic fields and rapid rotation of the progenitor. A number of the new beta-decay rates are for nuclei on or near the r-process path, and hence they affect the nucleosynthesis yields and time scale of the r-process. The main effect of the newly measured beta-decay half-lives is an enhancement in the calculated abundance of isotopes with mass number A = 110 -- 120 relative to calculated abundances based upon beta-decay rates estimated with the finite-range droplet mass model. This effect slightly alleviates, but does not fully explain, the tendency of r-process models to underproduce isotopes with A = 110 -- 120 compared to the solar-system r-process abundances.