Pseudo Spin Doublet Bands and Gallagher Moszkowski Doublet Bands in 100Y
New transitions in the deformed neutron-rich 100Y uniquely identified using the VAMOS++ spectrometer (A, Z) in conjunction with EXOGAM, produced in fission reactions of 238U on a 9Be target at energies around the barrier are reported. High spin states were obtained from an analysis of the large fold γ coincidence data from the spontaneous fission of 252Cf using the Gammasphere detector array. The new Kπ = 4+ band decaying to an isomeric state (1s) is assigned to be the high-K Gallagher-Moszkowski (GM) partner of the known Kπ = 1+ band, and is also proposed to be the pseudo spin (PS) partner of another new Kπ = 5+ band. Constrained triaxial covariant density functional and quantal particle rotor model calculations for the band structure and electromagnetic transition probabilities are in good agreement with the measurements. The work shows for the first time a coexistance of GM and PS bands in the same nucleus and could point towards a common source of these bands despite their very different origins.
