Exploration for Astromers near $^{132}$Sn with the Canadian Penning Trap

TL;DR

This paper reports direct mass measurements of isomeric states in tin isotopes near $^{132}$Sn, revealing their potential role as astromers affecting astrophysical nucleosynthesis and reaction rates.

Contribution

It provides the first direct mass measurements of specific isomeric states in tin isotopes near $^{132}$Sn and assesses their impact on astrophysical processes.

Findings

$^{129g,m}$Sn have measured mass excesses of -80593.2(25) keV and -80557.4(25) keV.

The excitation energy of $^{129m}$Sn is 35.8(35) keV.

$^{129g,m}$Sn behave as astromers during neutron capture in the i- and r-processes.

Abstract

Nuclear isomers can have significant impacts on astrophysical nucleosynthesis processes, with recent efforts demonstrating that the population of isomeric states with different half-lives may require separate treatment in reaction networks to accurately capture the differences in heating or in identifiable electromagnetic signals. Several potential so-called ``astromers'' in tin and antimony isotopes near doubly-magic $^{132}$Sn were identified and direct mass measurements of their ground and isomeric states were performed with the Canadian Penning Trap at Argonne National Laboratory's CARIBU facility, and their impact on astrophysical reaction rates and in reaction networks calculated. It was found that $^{129g,m}$Sn, with measured mass excesses of $-80 593.2(25)$ keV and $-80 557.4(25)$ keV, respectively, and an excitation energy of $35.8(35)$ keV, behaves as an astromer during neutron capture in the $i$-process and in the $r$-process.