Impact of dineutrons on nuclear compositions of a core-collapse supernova

Abstract

We study the nuclear compositions in the central region of a core-collapse supernova, assuming the existence of dineutrons (${}^{2}n$) and tetraneutrons (${}^{4}n$). At 100~ms after core bounce, ${}^{2}n$ and ${}^{4}n$ are more abundant than deuterons within radii of approximately 100 and 50~km, respectively. Compared to the model ignoring the existence of ${}^{2}n$ and ${}^{4}n$, the mass fraction of neutrons up to a radius of 100~km reduces, while the mass fractions of protons, deuterons, and ${}^4\mathrm{He}$ increase. Due to the uncertainties in the properties of ${}^{2}n$ and ${}^{4}n$, we investigate the influence of their binding energies on the nuclear composition. We find the binding energy of ${}^{2}n$ has only a modest effect on the overall composition, except for its own mass fraction, while that of ${}^{4}n$ has a negligible impact.

Comments: 6 pages, 9 figures, accepted for publication in Phys. Rev. C. Revised version with shortened content and updated title