Low-Spin Structure of <sup>58</sup>Cu and its Impact on the <sup>57</sup>Ni(p,γ)<sup>58</sup>Cu Reaction in the νp-Process
ORAL
Abstract
Antineutrino interactions can have an important impact on the final composition following explosive nucleosynthesis. During the νp process free neutrons are created and drive the composition toward stability via neutron reactions. Such extreme conditions may be found in environments like the dynamic ejecta of core-collapse or magneto-rotational supernovae. Uncertainties in the 57Ni(p,γ)58Cu reaction rate have shown a significant impact on astrophysical models and the final isotopic abundances in such scenarios. The low-lying level structure of 58Cu (N=Z) and the high-spin structure have been well studied. However, low-spin resonance states above the proton separation energy (Sp= 2.87 MeV), which can dominate the (p,γ) reaction rate, have yet to be measured or have large uncertainties. We conducted a high-resolution γγ-coincidence experiment at ATLAS using Gammasphere coupled to Neutron Shell. Low-spin states in 58Cu were preferentially populated via the 58Ni(p,n)58Cu reaction using a 17-MeV proton beam and deduced from gamma-ray angular distributions. We have identified many relevant low-spin levels with high excitation energy, covering most of the Gamow window. These data are used to constrain the astrophysical 57Ni(p,γ)58Cu reaction rate and reduce uncertainties in modeling the impact of the νp process. These results will be discussed as well as their influence explored within a single zone nuclear reaction model.
**This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Award Number DE-FG02-94ER40848 (UML).
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Presenters
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Sean Patrick Byrne
- University of Massachusetts Lowell