Evidence for two-particle configurations in deformed nuclei from beta transition rates

Abstract

All the known allowed beta-decays with log ft values up to 5.2 in the deformed nuclei are found to proceed through the underlying single-particle spin-flip transition p : [Nn3Λ↑] ⇌ n : [Mn3Λ↓] with N = n3 + Δ = 5. This observation provides a "strong" rule for configuration assignments to the involved levels in the parent and the daughter nuclei. We use this rule to deduce two-quasiparticle configurations for 42 levels, including several high spin isomers, in the doubly-odd, and 32 connected levels in the even-even, nuclei of the rare earth region. The experimentally observed level energies are compared with the theoretically expected band head energies for the assigned two-particle configurations.