Prompt Proton Decay of a Well-Deformed Rotational Band in58Cu

Exotic Decay Modes in Rotating Nuclei

“…the mass region [1]. In the present case, however, no significant shape change should be associated with the decay, which further enhances its likelihood.…”

“…The experimental knowledge concerning the prompt proton decays has been increased systematically following the first observation of the decay mode [1] at Gammasphere [7]. The focus has been on 58 Cu, where spins and parities of the initial and final state could be assigned [5,8,9] and lifetimes of γ-and proton-decaying states have been measured in the decay-out regime of the rotational band [5,10] ?…”

“…The first case of prompt proton emission from excited high-spin states in the well-deformed second minimum of the nuclear potential into spherical daughter states was identified in 58 Cu [1]. In the following years, additional prompt proton decays have been found in 56 Ni [2] and 59 Cu [3], and a case of prompt α-particle emission has been observed in 58 Ni [4].…”

“…They may be viewed as self-regulated two-dimensional quantum tunneling processes: The problem is two-dimensional, because the initial states have prolate deformation with a long-to-short axis ratio of about 1.5:1 (see, e.g., Refs. [1,5]). The process is self-regulated, because the emission of the particles induces a drastic rearrangement of the nuclear meanfield potential, since the final states are spherical or even slightly oblate deformed.…”

Exotic nuclei from a theoretical perspective

“…Here, spectacular examples are proton-emitting intruder bands in 58Cu [41] and 56Ni [42]. In 56Ni, where two intruder bands have been observed, the lower rotational band can be explained by large-scale shell-model calculations in the pf shell.…”