Superdeformation in asymmetric N>Z nucleus 40Ar

A rotational band with five γ-ray transitions ranging from 2+ to 12+ states was identified in 40Ar. This band is linked through γ transitions from the excited 2+, 4+ and 6+ levels to the low-lying states; this determines the excitation energy and the spin-parity of the band. The deduced transition quadrupole moment of 1.45−0.31+0.49±0.15 eb indicates that the band has a superdeformed shape. The nature of the band is revealed by cranked Hartree-Fock-Bogoliubov calculations and a multiparticle-multihole configuration is assigned to the band.