2017/01/31 by Shun Furusawa, Hiroki Nagakura, Kohsuke Sumiyoshi +3 · 34 citations
Physics and Astronomy · #Astronomical and nuclear sciences #Astrophysics #Atomic physics #Electron #Electron capture #Electron scattering #Gamma-ray bursts and supernovae #Materials science #Neutrino #Nuclear physics #Nuclear physics research studies #Nuclear reaction #Nucleosynthesis #Nucleus #Physics #Quantum mechanics #Scattering #Shell (structure) #Stars #Supernova #astro-ph.HE #nucl-th
paper · pdf · doi:10.1103/physrevc.95.025809
published in Physical Review C 95(2) (American Institute of Physics) · 28 pages 14 figures, accepted for publication in Phys. Rev. C
openalex created_date 2017/02/10 · openalex publication_date 2017/02/24 · arxiv created 2017/03/18 · arxiv updated 2017/03/21 · openalex updated_date 2026/08/06
We investigate the influences of the nuclear composition on the weak interaction rates of heavy nuclei during the core collapse of massive stars. The nuclear abundances in nuclear statistical equilibrium (NSE) are calculated by some equation of state (EOS) models including in-medium effects on nuclear masses. We systematically examine the sensitivities of electron capture and neutrino-nucleus scattering on heavy nuclei to the nuclear shell effects and the single-nucleus approximation. We find that the washout of the shell effect at high temperatures brings significant change to weak rates by smoothing the nuclear abundance distribution: the electron capture rate decreases by \ensuremath∼20% in the early phase and increases by \ensuremath∼40% in the late phase at most, while the cross section for neutrino-nucleus scattering is reduced by \ensuremath∼15%. This is because the open-shell nuclei become abundant instead of those with closed neutron shells as the shell effects disappear. We also find that the single-nucleus description based on the average values leads to underestimations of weak rates. Electron captures and neutrino coherent scattering on heavy nuclei are reduced by \ensuremath∼80% in the early phase and by \ensuremath∼5% in the late phase, respectively. These results indicate that NSE like EOS accounting for shell washout is indispensable for the reliable estimation of weak interaction rates in simulations of core-collapse supernovae.