Delayed Multineutron Emission in the Region of Heavy Calcium Isotopes

A brief survey of self-consistent models used to perform global calculations of β-decay properties of neutron-rich nuclei is given. These models include the continuum quasiparticle randomphase approximation (CQRPA) based on the energy density functional (DF) proposed by Fayans and his colleagues (DF + CQRPA), relativistic quasiparticle random-phase approximation (RQRPA), and the finite-amplitude method (FAM). These models take into account allowed Gamow–Teller transitions and first-forbidden transitions. Models that allow for complex configurations beyond the QRPA framework are also analyzed. The β-decay properties of heavy calcium, potassium, and scandium isotopes in the vicinity of the N = 32 and 34 neutron subshells, which are new magic subshells for neutrons, are calculated on the basis of the self-consistent DF + CQRPA approach. The predicted high probability for two-neutron emission is found to be correlated with the anomalous nuclear radii measured for potassium and calcium isotopes in the region around N = 32. The results ofDF3 + CQRPA calculations are compared with their counterparts obtained within the self-consistent models implemented with the SkO’ Skyrme functional and the D3C* relativistic functional.