Multi-quasiparticle isomers inLu174

Abstract

Four-, six-, and eight-quasiparticle isomers with K π = 14 − , (21 + ) and (26 − ) have been identified in the deformed nucleus 174 Lu, in addition to the previously reported K π = 13 + , four-quasiparticle isomeric state.Analysis of alignments and in-band crossover-to-cascade branching ratios lead to the characterization of the configurations associated with the K π = 14 − and (21 + ) isomers. The excitation energies of the observed states are compared with results from multi-quasiparticle calculations that include effects of blocking and residual nucleon-nucleon interactions. Good agreement is found for medium-spin (I = 13-14h) and the highest spin (I > 20h) states observed, but there remain ambiguities in assigning configurations in the I = 15-19h region.

Particle-number conserving analysis for the 2-quasiparticle and high- K multi-quasiparticle states in doubly-odd 174,176 Lu

“…The results are quite similar to those multi-qp blocking calculations in Ref. [28]. For the state at 4710 keV, the calculated energies of the two configuration assignments K π = 22 + and K π = 22 − are both close to the data.…”

“…So these two configurations are all possible for the observed state with excitation energy 4710 keV, which is consistent with the conclusion in Ref. [28]. Later on, the possible configuration assignments for K + = 14 − , 15 + , and 16 + will be analyzed according to the MOI's.…”

“…For the calculations of the excitation energies and the MOI's, the configuration assignments can be reasonably made. [22,23,27,28,50]. b An alternative configuration for K π = 14 − , which is denoted as Config1 in Fig.…”

“…With the development of experimental techniques, more and more measurements have been done for the neutron rich nuclei. As for the neutron rich doubly-odd Lu nuclei, many experiments have been performed not only for the 2-quasiparticle (qp) structures, but also for the high-K multi-qp isomers [21][22][23][24][25][26][27][28][29]. * Supported by NSFC (Grant No.…”

Review of metastable states in heavy nuclei

“…The measurements have led to extensive new information on isomers in a range of nuclei near stability and also somewhat neutron-rich, as depicted schematically in figure 24. Analysis of these data continues but details of completed results are published in a series of papers [33,67,74,94,126,128,129,130,443,444,445,446,447,448,449,450,451]. They cover a broad range in terms of physics, from the characterisation of comprehensive multi-quasiparticle isomers in 174 Yb [445], for example, to the identification of transitions to intermediate states that could connect the high-K and low-K isomeric and ground states in 176 Lu by photoexcitation, thus affecting elemental abundances in a stellar environment [33].…”