Triaxial superdeformation in $^{40}$Ar

TL;DR

This study investigates superdeformed states in $^{40}$Ar using advanced nuclear modeling techniques, revealing a triaxial superdeformed band and its properties consistent with experimental data.

Contribution

It introduces a comprehensive theoretical approach combining AMD, AMP, and GCM to describe triaxial superdeformation in $^{40}$Ar, highlighting the importance of triaxiality.

Findings

Identification of a superdeformed band just above the ground state

Discovery of a $K^^+$ side band due to triaxiality

Reproduction of experimental electric quadrupole transition strengths

Abstract

Superdeformed (SD) states in $^{40}$Ar have been studied using the deformed-basis antisymmetrized molecular dynamics. Low energy states were calculated by the parity and angular momentum projection (AMP) and the generator coordinate method (GCM). Basis wave functions were obtained by the energy variation with a constraint on the quadrupole deformation parameter $\beta$, while other quantities such as triaxiality $\gamma$ were optimized by the energy variation. By the GCM calculation, an SD band was obtained just above the ground state (GS) band. The SD band involves a $K^\pi = 2^+$ side band due to the triaxiality. The calculated electric quadrupole transition strengths of the SD band reproduce the experimental values appropriately. Triaxiality is significant for understanding low-lying states.