High-precision mass measurements of the ground and isomeric states in $^{124,125}$Ag

TL;DR

This study provides highly precise mass measurements of $^{124,125}$Ag isotopes, revealing new excitation energies, refining nuclear structure understanding, and significantly reducing uncertainties in astrophysical neutron-capture rates.

Contribution

The paper introduces the first measurement of the excitation energy of $^{124}$Ag$^{m}$ and improves mass precision for $^{124,125}$Ag, impacting nuclear structure and astrophysical models.

Findings

First measurement of $^{124}$Ag$^{m}$ excitation energy at 188.2(25) keV.

Mass values are 36 and 110 times more precise than previous data.

Reduced uncertainties in neutron-capture rate calculations by a factor of 100.

Abstract

The masses of the ground and isomeric states in $^{124,125}$Ag have been measured using the phase-imaging ion-cyclotron-resonance technique at the JYFLTRAP double Penning trap mass spectrometer. The ground states of $^{124}$Ag and $^{125}$Ag were found to be 30(250) keV and 250(430) keV less bound but 36 and 110 times more precise than in the Atomic Mass Evaluation 2020, respectively. The excitation energy of $^{124}$Ag$^{m}$, ${E_x = 188.2(25)}$ keV, was determined for the first time. The new precise mass values have been utilised to study the evolution of nuclear structure via two-neutron separation energies. The impact on the astrophysical rapid neutron capture process has been investigated via neutron-capture reaction rate calculations. The precision measurements indicate a more linear trend in two-neutron separation energies and reduce the mass-related uncertainties for the neutron-capture rate of $^{124}$Ag$(n,\gamma)^{125}$Ag by a factor of around 100. The new mass values also improve the mass of $^{123}$Pd, previously measured using $^{124}$Ag as a reference.