High-spin proton emitters in odd-odd nuclei and shape changes

Abstract

We present a formalism to describe proton emission from odd-odd nuclei based on a scattering like approach. Special emphasis is given to the case of transitions between states with different deformations. As an example we estimate the proton half-life of the odd-odd nucleus 58 Cu. Our calculations show that the change of deformation in the decay process has a significant influence on the half-life. In addition, the angular momentum coupling of proton and neutron orbitals can result in an important K-hindrance of the decay. To fully account for the observed half-life in 58 Cu, one has to consider a shape mixing in the final state.

Isospin and deformation studies in the odd-oddN=ZnucleusCo54

“…Since 54 Co is a weak reaction channel, the raw 1α1p1n γ -ray spectra and matrices comprise significant contributions from the much more intense 1α2p1n reaction channel 53 Fe [26] and, less pronounced, from the 1α3p1n channel 52 Mn, from the 2α1p1n channel 50 Mn, as well as from 51 Mn (2α1p), 53 Mn (1α3p), 55 Fe (4p1n), and 56 Co (3p1n). The former three contaminations arise from events when one or more charged particles escaped the detection in Microball.…”

“…Indeed, discrete-energy proton and α "linking transitions" between well-deformed rotational states in the mother nucleus and near-spherical states in the respective daughter nucleus have been observed in nearby nuclei, e.g., proton decays from bands in 56 Ni [3,45] and 58 Cu [23,46], or α decays from two rotational states in 58 Ni [47,48], while principally, of course, any excited state above particle threshold may exhibit particle decay branches, deformed or not. For instance, in case of rotational bands populated via fusion-evaporation reactions, this has been studied by Døssing and coworkers [49], while the hindrance factor induced for the specific proton decay from the deformed band in 58 Cu [46] has been explained by a combination of the change of the nuclear shape and the change of the K quantum number of a 1g 9/2 neutron "spectator" [50].…”

High-spin isomeric structures in exotic odd-odd nuclei: Exploration of the proton drip line and beyond

“…In Ref. [32], it has been pointed out that different K values in the wave functions of the mother and the daughter can result in an additional K hindrance of the proton decay. These would provide the possibility to extend the nuclide territory further beyond the proton-drip line.…”

Proton emission from triaxial nuclei

“…[20]. Recently, also odd-odd nuclei have been measured [21,22] and theoretically analyzed [23,24]. However, in all these cases it has been assumed that the mother and the daughter nuclei are spherical or, if deformed, have cylindrical symmetry.…”