A new phenomenon - shifted identical bands

Abstract

From spontaneous fission data in the prompt [gamma]-ray emission of 252Cf, the isotopes 162Gd and 160Sm were identified and the level schemes of 160Gd and 158Sm were extended. From over 700 comparisons of even-even yrast bands from Xe to Os separated by 2n, 2p, [alpha], 4n, 4p, 2[alpha], [alpha]+2n, [alpha]+2p, 2n-2p, and other cases, from the ground state to 8+ and sometimes as high as 18+, 55 ground state shifted identical bands (SIB) and 4 identical bands (IB) were found. After the shift, these SIBs are seen to be more identical than previously known IBs and are not correlated with (NpNn)(NpNn)', [beta]2[beta]'2, E(4+)/E(2+), saturation of collectivity, or with the variation in the ground band - s band interaction strength. They are seen only in well-deformed stable to most neutron rich nuclei from Nd to Hf, and are not seen in [gamma] bands.