2026/08/04 by A. C. Larsen, M. Guttormsen, T. K. Eriksen +22
Physics and Astronomy · #nucl-ex #nucl-th
We present a study on the γ-decay properties of 64Zn using the Oslo method on 64Zn(p,p^′ γ) data combined with 64Zn(γ,n) cross-section measurements at the NewSUBARU facility. With the Oslo method, we have measured the γ-ray strength function (γSF) and the nuclear level density (NLD) below the neutron threshold. We observe that the NLD trend in the quasi-continuum region of 64Zn is best characterized by a constant-temperature-like model. %with temperature parameter T\rm CT=1.21(5) MeV. Surprisingly, we find that γ-ray transitions from the quasi-continuum decaying directly to the 0+ ground state seem to be strongly hindered with a hindrance factor of κ≈ 0.5, which could be an indication of non-statistical effects in the ground-state decay due to, e.g., differences in nuclear shapes. For γ energies above the neutron separation energy, the NewSUBARU (γ, n) data set probes a significant part of the giant dipole resonance. Furthermore, we find that the Oslo-method γSF shows a rather smooth behavior, with a clear low-energy enhancement (LEE) for Eγ < 4 MeV.