The 76Cu conundrum remains unsolved

Abstract

Near the doubly-magic nucleus \nuc{Ni}{78} ($Z=28$, $N=50$), there has been a decades-long debate on the existence of a long-lived isomer in \nuc{Cu}{76}. A recent mass measurement claimed to have settled the debate, by measuring the energy of the isomer and shedding light on the structure of the nucleus. In this work, we present new, more accurate, and precise values of the half-lives of the isomeric and ground states in \nuc{Cu}{76}. Our findings suggest that both states have very similar half-lives, in the 600-700 ms range, in disagreement with the literature values, implying that they cannot be differentiated by their decay curves. These results raise more questions than they answer, reopening the debate and showing that the structures in \nuc{Cu}{76} are still not fully understood.

References in corpus (12)

• Enhanced Stability of Superheavy Nuclei due to High-Spin Isomerism
• High-precision mass measurements of nickel, copper, and gallium isotopes and the purported shell closure at N=40
• Half-lives and branchings for β-delayed neutron emission for neutron-rich Co-Cu isotopes in the r-process
• Astromers: Nuclear Isomers in Astrophysics
• Atlas of Nuclear Isomers -- Second Edition
• Structure of 65,67Co studied through the beta decay of 65,67Fe and a deep-inelastic reaction
• Dipole and quadrupole moments of ${}^{73-78}$Cu as a test of the robustness of the $Z=28$ shell closure near ${}^{78}$Ni
• Commissioning of the BRIKEN detector for the measurement of very exotic beta-delayed neutron emitters
• Odd-odd neutron-rich rhodium isotopes studied with the double Penning trap JYFLTRAP
• Detailed spectroscopy of doubly magic ${}^{132}$Sn
• First $\beta$-decay spectroscopy of ${}^{135}$In and new $\beta$-decay branches of ${}^{134}$In
• Fast-timing study of ${}^{81}$Ga from the $\beta$ decay of ${}^{81}$Zn