학술논문
High-precision mass measurements of neutron deficient silver isotopes probe the robustness of the $N$ = 50 shell closure
Document Type
Working Paper
Author
Ge, Z.; Reponen, M.; Eronen, T.; Hu, B. S.; Kortelainen, M.; Kankainen, A.; Moore, I. D.; Nesterenko, D. A.; Yuan, C. X.; Beliuskina, O.; Cañete, L.; de Groote, R.; Delafosse, C.; Delahaye, P.; Dickel, T.; de Roubin, A.; Geldhof, S.; Gins, W.; Holt, J. D.; Hukkanen, M.; Jaries, A.; Jokinen, A.; Koszorús, Á.; Kripko-Koncz, G.; Kujanpää, S.; Lam, Y. H.; Nikas, S.; Ortiz-Cortes, A.; Penttilä, H.; Pitman-Weymouth, D.; Plaß, W.; Raggio, A.; Rinta-Antila, S.; Romero, J.; Stryjczyk, M.; Vilen, M.; Virtanen, V.; Zadvornaya, A.
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Subject
Language
Abstract
High-precision mass measurements of exotic $^{95-97}$Ag isotopes close to the $N = Z$ line have been conducted with the JYFLTRAP double Penning trap mass spectrometer, with the silver ions produced using the recently commissioned inductively-heated hot cavity catcher laser ion source at the Ion Guide Isotope Separator On-Line facility. The atomic mass of $^{95}$Ag was directly determined for the first time. In addition, the atomic masses of $\beta$-decaying 2$^+$ and 8$^+$ states in $^{96}$Ag have been identified and measured for the first time, and the precision of the $^{97}$Ag mass has been improved. The newly measured masses, with a precision of $\approx$ 1 keV/c$^2$, have been used to investigate the $N =$ 50 neutron shell closure confirming it to be robust. Empirical shell-gap and pairing energies determined with the new ground-state mass data are compared with the state-of-the-art \textit{ab initio} calculations with various chiral effective field theory Hamiltonians. The precise determination of the excitation energy of the $^{96m}$Ag isomer in particular serves as a benchmark for \textit{ab initio} predictions of nuclear properties beyond the ground state, specifically for odd-odd nuclei situated in proximity to the proton dripline below $^{100}$Sn. In addition, density functional theory (DFT) calculations and configuration-interaction shell-model (CISM) calculations are compared with the experimental results. All theoretical approaches face challenges to reproduce the trend of nuclear ground-state properties in the silver isotopic chain across the $N =$50 neutron shell and toward the proton drip-line.
Comment: 9 pages, 3 figures
Comment: 9 pages, 3 figures