Unveiling New States in ⁹⁸Zr: Insights from β-decay and γ-γ Angular-Correlation Studies

¹ label>Department of Physics, University of Guelph, Guelph, Canada
² Instituto de Estructura de la Materia, CSIC, Madrid, Spain
³ Department of Chemistry, Simon Fraser University, Burnaby, Canada
⁴ TRIUMF, Vancouver, Canada
⁵ Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, USA
⁶ FRIB, Michigan State University, East Lansing, USA
⁷ Center for Exotic Nuclear Studies, IBS, Daejeon, Republic of Korea
⁸ Department of Chemistry, University of Kentucky, Kentucky, USA
⁹ Department of Physics & Astronomy, McMaster University, Hamilton, Canada
¹⁰ Department of Physics, Georgia Institute of Technology, Georgia, USA

^* e-mail: kmastako@uoguelph.ca

Published online: 25 June 2025

Abstract

The nuclear structure of the ⁹⁸Zr nucleus was studied through the β⁻ decay of ⁹⁸ Y_g.s. at the TRIUMF-ISAC facility. The use of the 8π γ-ray spectrometer with its ancillary detectors SCEPTAR and PACES enabled γ-γ and γ-e⁻ coincidence measurements as well as γ-γ angular correlations. The level spin assignments and transition mixing ratios obtained in this study were in good agreement with previous results. Furthermore, 12 previously unknown states in the low-energy region of ⁹⁸Zr were identified, including the 0⁺₅ and 0⁺₆ levels at 2418 and 2749 keV, respectively. The 2⁺ and I = 1 natures for multiple newly observed and previously known (but not firmly assigned) states have been established. Additionally, the previously assumed pure E2 character of the 2⁺₂ → 2⁺₁ 367.8-keV transition was confirmed.