Effects of Beta-Decays of Excited-State Nuclei on the Astrophysical r-Process

TL;DR

This paper estimates how beta-decays of excited nuclei influence the r-process in astrophysics, using a simplified model across thousands of nuclei within supernova conditions to understand their impact on element formation.

Contribution

It introduces a first-order calculation of excited-state beta-decays in r-process nucleosynthesis, integrating a phenomenological decay rate model into extensive network simulations.

Findings

Excited-state beta-decays can significantly affect r-process abundances.

The model covers all nuclei with A<284 involved in the r-process.

Results provide an initial estimate of excited-state decay effects on nucleosynthesis.

Abstract

A rudimentary calculation is employed to evaluate the possible effects of beta- decays of excited-state nuclei on the astrophysical r-process. Single-particle levels calculated with the FRDM are adapted to the calculation of beta-decay rates of these excited-state nuclei. Quantum numbers are determined based on proximity to Nilson model levels. The resulting rates are used in an r-process network calculation in which a supernova hot-bubble model is coupled to an extensive network calculation including all nuclei between the valley of stability and the neutron drip line and with masses A<284. Beta-decay rates are included as functional forms of the environmental temperature. While the decay rate model used is simple and phenomenological, it is consistent across all 3700 nuclei involved in the r-process network calculation. This represents an approximate first estimate to gauge the possible effects of excited-state beta-decays on r-process freeze-out abundances.