Cluster-breaking and reconfiguration effects in $_\Lambda^{12}\rm{B}$ hypernucleus

Jiaqi Tian; Mengjiao Lyu; Akinobu Dote; Zheng Cheng; Takayuki Myo; Masahiro Isaka; Hisashi Horiuchi; Hiroki Takemoto; Hiroshi Toki; Niu Wan; Qing Zhao

arXiv · 2508.11937

Cluster-breaking and reconfiguration effects in $_\Lambda^{12}\rm{B}$ hypernucleus

Jiaqi Tian·Mengjiao Lyu·Akinobu Dote·Zheng Cheng·Takayuki Myo·Masahiro Isaka·Hisashi Horiuchi·Hiroki Takemoto·Hiroshi Toki·Niu Wan·Qing Zhao

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Abstract

We investigate the cluster-breaking effect and spatial distribution of negative-parity states in the $_\Lambda^{12}\rm{B}$ hypernucleus using the Hyper-Brink model with cluster-breaking(CB-Hyper-Brink) optimized via Control Neural Network (Ctrl.NN). The results demonstrate that the inclusion of cluster-breaking is essential for accurately reproducing the observed low-lying energy levels and for making reliable predictions of the Hoyle-analog state 1-4 in $_\Lambda^{12}\rm{B}$. Cluster-breaking manifests as strong spin-orbit correlations and the dissolution of ideal cluster configurations, as revealed by the analysis of one-body spin-orbit operator expectation values and the spatial overlap with projected cluster bases. The interplay between short-range repulsion and intermediate-range attraction in the Lambda N interaction induces the cluster reconfiguration effect, which is characterized by the coexistence of Lambda-alpha and Lambda-triton correlations; this reconfiguration effect leads to a modest stabilization and shrinkage of cluster structures. The variation in electric quadrupole transition strengths, B(E2), between the ground and Hoyle-analog states serves as a sensitive probe for the degree of cluster-breaking, providing direct evidence for its physical relevance. These findings highlight the crucial role of cluster-breaking in characterizing the hypernuclear structure and offer a comprehensive framework for understanding the interplay between clustering and shell-model dynamics in hypernuclei.

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Jiaqi Tian, Mengjiao Lyu, Akinobu Dote, Zheng Cheng, Takayuki Myo, Masahiro Isaka, Hisashi Horiuchi, Hiroki Takemoto, Hiroshi Toki, Niu Wan, Qing Zhao. 2025-08-16. Cluster-breaking and reconfiguration effects in $_\Lambda^{12}\rm{B}$ hypernucleus. https://arxiv.org/abs/2508.11937

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