Container structure of alpha alpha Lambda clusters in ${}_{\Lambda }^9$Be

Abstract

New concept of clustering is discussed in $\Lambda$ hypernuclei using a new-type microscopic cluster model wave function, which has a structure that constituent clusters are confined in a container, whose size is a variational parameter and which we refer to as Hyper-Tohsaki-Horiuchi-Schuck-Röpke (Hyper-THSR) wave function. By using the Hyper-THSR wave function, $2\alpha +\Lambda$ cluster structure in ${}_{\Lambda }^9\mathrm{Be}$ is investigated. We show that full microscopic solutions in the $2\alpha +\Lambda$ cluster system, which are given as $2\alpha +\Lambda$ Brink-GCM wave functions, are almost perfectly reproduced by the single configurations of the Hyper-THSR wave function. The squared overlaps between the both wave functions are calculated to be $99.5$%, $99.4$%, and $97.7$% for $J^{\pi }=0^{+}$, $2^{+}$, and $4^{+}$ states, respectively. We also simulate the structural change by adding the $\Lambda$ particle, by varying the $\Lambda N$ interaction artificially. As the increase of the $\Lambda N$ interaction, the $\Lambda$ particle gets to move more deeply inside the core and invokes strongly the spatial core shrinkage, and accordingly distinct localized $2\alpha$ clusters appear in the nucleonic intrinsic density, though in ${}^8\mathrm{Be}$ rather gaslike $2\alpha$-cluster structure is shown. The origin of the localization is associated with the strong effect of Pauli principle. We conclude that the container picture of the $2\alpha$ and $\Lambda$ clusters is essential in understanding the cluster structure in ${}_{\Lambda }^9\mathrm{Be}$, in which the very compact spatial localization of clusters is shown in the density distribution.

14 pages, 4 figures, 3 tables, submitted to PTEP

References in corpus (1)

• Deformation of hypernuclei studied with antisymmetirzed molecular dynamics

Cited by in corpus (11)

• Hoyle band and $\alpha$ condensation in ${}^{12}\mathrm{C}$
• Investigation of 10Be and its cluster dynamics from nonlocalized clustering concept
• Nonlocalized Clustering and Evolution of Cluster Structure in Nuclei
• Container evolution for cluster structures in ${}^{16}\mathrm{O}$
• Monopole excitation of the Hoyle state and linear-chain state in 12C
• Resonant and Scattering States in the $\alpha +\alpha$ System from the Non-Localized Cluster Model
• Excitation energy shift and size difference of low-energy levels in $p$-shell $\Lambda$ hypernuclei
• New trial wave function for nuclear cluster structure of nuclei
• Structures of $p$-shell double-$\Lambda$ hypernuclei studied with microscopic cluster models
• Cluster structures of the $0^{+}$ states of ${}_{\Lambda }^{13}\mathrm{C}$ with the 3$\alpha +\Lambda$ four-body orthogonality condition model
• Structure of the ground and excited states in ${}_{\Lambda }^9$Be nucleus