Mass of self-conjugate nucleus 80Zr reveals a deformed double shell closure at N=Z=40
Abstract
The neutron-deficient region around 80Zr is an area of great interest for nuclear structure due to the rapid change in nuclear shape with proton and neutron numbers. For the self-conjugate 80Zr nucleus, spherical and deformed structures are expected to coexist at low energies, and their competition strongly depends on the size of the calculated N=Z=40 gap. In addition to shape-coexistence effects, 80Zr offers a venue to study the Wigner energy reflecting an additional binding in self-conjugate nuclei and their neighbors. Mass differences can be used to probe the strength of these effects; however, mass data in the region is sparse. In this talk, I will present results from the first Penning trap mass measurement of 80Zr using the Low Energy Beam and Ion Trap (LEBIT) facility at the National Superconducting Cyclotron Laboratory. Our measurement reveals a significant enhancement in the binding energy of 80Zr. Through binding-energy indicators, we attribute this enhancement to the deformed double shell closure at N=Z=40 and an increase in the Wigner energy of this exotic system. A statistical Bayesian model mixing analysis employing eleven global nuclear mass models demonstrates difficulties with reproducing the observed mass anomaly using current theory.
This work was conducted with the support of Michigan State University, the U.S. National Science Foundation under Contract No. PHY-1565546, the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Award Nos. DE-SC0015927, DE-SC0013365, and DE-SC0018083 (NUCLEI SciDAC-4 collaboration), and by the National Science Foundation CSSI program under Award Number 2004601 (BAND collaboration).- Publication:
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APS Division of Nuclear Physics Meeting Abstracts
- Pub Date:
- 2021
- Bibcode:
- 2021APS..DNP.LG002H