Cluster-shell competition and effect of adding hyperons

doi:10.1103/PhysRevC.107.024309

2023-02-16

N. Itagaki *

Emiko Hiyama

DOI：10.1103/PhysRevC.107.024309

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摘要

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Background: The fundamental question is how the hyperon plays a role in the nuclear structure. It is of particular importance, especially in the light mass region, to verify the structure change when A particle(s) is added to normal nuclei.Purpose: The ground state of 8Be has been known to have a well-developed alpha-alpha cluster structure, whereas 12C has a mixed structure of three alpha clusters and j j-coupling shell model, where alpha clusters are partially broken. Adding A particle(s) could induce the structure change. We compare the Be and C cases.Methods: Using the antisymmetrized quasicluster model (AQCM), the alpha-cluster states and j j-coupling shell -model states of 8Be and 12C are prepared on the same footing, and we add A particles. The cluster-shell competition in the ground state can be well described with this model. Using AQCM, we calculate 8Be, 9ABe, AABe, 12C, 13 10 A C, and 14AAC.Results: By adding one or two A particle(s), the ground state of 12C approaches the j j-coupling shell model side. On the other hand, in the Be case, although the A particle(s) shrinks the alpha-alpha distance, the breaking effect of the cluster structure is rather limited.Conclusions: The spin-orbit interaction is the driving force of breaking the alpha clusters, and whether the glue-like effect of A particle(s) attracts the cluster inside the range of this interaction is crucial. In 14AAC, the breaking of alpha clusters in 12C is much enhanced by the addition of the A particles than the case of free 12C. We also found that breaking alpha clusters in the ground state of 14AAC affects the excited state with the pure cluster structure.

Keyword:

LAMBDA-HYPERNUCLEI

EXCITED-STATES

C-13(LAMBDA)

MODELS