Exotic Decay Modes in Rotating Nuclei

Abstract

Recent results and experiments are presented aiming at nuclear structure studies in the vicinity of the doubly-magic isotope 56 Ni. The feature of prompt particle emission is revised, and new studies of mirror nuclei in the upper fp shell are briefly discussed.

Triplet energy differences and the low lying structure ofGa62

“…To try to shed some light on the likely location of the T = 1, 2 + state, it is worth considering systematics of T = 1 triplets. This is now possible for nuclei across the whole f pg shell due to spectroscopic studies in the last decade that have allowed observation of the T = 1 excited states in the difficult-to-access T z = 0 N = Z nuclei and the proton rich nuclei with T z = −1 [7,18,22,24,[26][27][28][29][30][31][32][33][34]. The pattern of excitation energies for the T = 1, 2 + states among the triplet show a remarkably consistent behavior as a function of mass number.…”

“…The currently assigned datum for the A = 62 triplet is bracketed. The data for the f pg shell, which are generally the most recent, can be found in the following references: A=42 [23], A=46 [22,24], A=50 [26,27], A=54 [7], A=58 [28,29], A=62 [18,34], A=66 [30,31], A=74 [32,33].…”

“…A simple empirical observation is that all the published data on TED lie in a narrow range, as demonstrated by the shaded region. The exception is the A = 62 system, where the tentatively assigned T = 1, 2 + states in 62 Ge and 62 Ga, at 964keV and 1017keV respectively, have been used [18,34]. The stark difference in this case suggests that at least one of the hitherto tentative assignments of the 62 Ga or 62 Ge T = 1, 2 + states may be wrong.…”

Isospin-symmetry breaking corrections for the description of triplet energy differences

“…For A = 62, there is some experimental uncertainty on the precise location of the T = 1 yrast states of T z = 0 62 Ga and T z =−1 62 Ge. T = 12 + and 4 + states were suggested by Rudolph et al [22]for 62 Ge following the tentative observation of two γ rays of 964 and 1321 keV, assumed to be the decays of the 2 + and 4 + states. These assignments await experimental confirmation.…”

Anomalies in fracture experiments, and energy exchange between vibrations and nuclei

“…However, there are examples of long-lived nuclear states near Fe that are observed to be stable against gamma decay, but unstable against highly asymmetric fission. The closest relevant studies involve high rotational bands in Co, Ni and Cu isotopes by Rudolph et al [92][93][94][95][96], where states at the band edges are deformed, relatively long-lived, and decay slowly through exotic high spin proton or alpha ejection. Consider the situation where up-conversion by inverse fractionation is effective in coupling to transitions at lower energy (6-10 MeV) where these longer-lived states can be accessed.…”