Tetrahedral shape and Lambda impurity effect in ⁸⁰Zr with a multidimensionally constrained relativistic Hartree-Bogoliubov model*

Abstract This study investigated the tetrahedral structure in 80 Zr and Lambda (Λ) impurity effect in Zr using the multidimensionally constrained relativistic Hartree-Bogoliubov model. The ground states of both 80 Zr and Zr exhibit a tetrahedral configuration, accompanied by prolate and axial-octupole shaped isomers. Our calculations reveal that there are changes in the deformation parameters , , and upon Λ binding to 80 Zr, except for when Λ occupies p -orbits. Compared to the two shape isomers, the Λ particle exhibits weaker binding energy in the tetrahedral state when occupying the or single-particle state. In contrast, the strongest binding occurs for the Λ particle in the state with tetrahedral shape. Besides, a large Λ separation energy may not necessarily correlate with a significant overlap between the density distributions of the Λ particle and nuclear core, particularly for tetrahedral hypernuclei.