Contrasting behavior in the rotational structure of the T-z=1/2 nuclei Kr-73 and Rb-75 : A possible fingerprint of T=0 neutron-proton pairing correlations

Three different rotational bands have been observed to high spin in Rb-75 using Gammasphere. The structures are similar, but not identical to those found in the neighboring T-z=1/2 nucleus Kr-73. Conventional total Routhian surface (TRS) calculations with T=1 pairing are able to reproduce the rotational bands in Rb-75 with extreme accuracy, but they completely fail in reproducing the spectra and decay pattern of the negative parity bands in Kr-73. Simple qualitative arguments are put forward to show that the decay pattern observed in the negative parity bands in Kr-73 can be accounted for by means of T=0 pair correlations. To further corroborate this scenario, deformation, and pairing self-consistent TRS calculations, including schematic T=1 and T=0 pairing, are performed for the first time indicating the onset of dynamical T=0 pair-correlations at high angular momenta.
QC 20100525