Signature splitting in three-quasineutron rotational band 3/2[521]_ν 1/2[660]_ν 1/2[660]_νof ¹⁵⁵Dy*

Abstract The signature splitting observed in the 3/2[521] ν ↑ 1/2[660] ν ↑ 1/2[660] ν ↑ three-quasineutron rotational band of 155 Dy is examined within the framework of axially symmetric three-quasiparticle plus axially symmetric rotor model. The experimental level energies and magnitudes of observed splitting are well-reproduced with RMS deviations of 68.13 keV and 0.58 keV, respectively. The major contributing bands in the observed splitting are K π =7/2 – :5/2[512] ν ↑ 3/2[651] ν ↑ 1/2[660] ν ↓, K π =5/2 – : 5/2[512] ν ↑ 3/2[651] ν ↑ 3/2[651] ν ↓, K π =1/2 – :3/2[521] ν ↑ 1/2[660] ν ↑ 3/2[651] ν ↓, K π =1/2 – : 3/2[521] ν ↓ 1/2[660] ν ↑ 3/2[651] ν ↑, K π =5/2 – :3/2[521] ν ↑ 3/2[651] ν ↑ 1/2[660] ν ↓, and K π =3/2 – : 3/2[521] ν ↑ 3/2[651] ν ↑ 3/2[651] ν ↓, which mix through rotor-particle (Δ K =1) and particle-particle (Δ K =0) couplings among the bands comprising the given basis space. The observed signature splitting is also well-reproduced by the superposition of calculated energy staggering of the strongly interacting bands, which further strengthens the validity of present particle rotor model calculations. Based on the present calculations, we assign the bandhead spin K π = 3/2 – to the band under discussion. Additionally, the locations of 13 low-lying band members in the spin range I π =3/2 – to 23/2 – and at 27/2 – and 31/2 – are predicted, which will be useful for future experimental investigations.