A new phenomenon - shifted identical bands

Abstract

From spontaneous fission data in the prompt γ-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, α, 4n, 4p, 2α, α+2n, α+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 (N p N n )(N p N n )′, β 2β′ 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 γ bands.