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

TL;DR

This study explores how hypothetical dineutrons and tetraneutrons could influence nuclear compositions in a supernova core, revealing significant abundance changes and sensitivity to their properties.

Contribution

It introduces the impact of dineutrons and tetraneutrons on supernova nuclear compositions, a novel consideration in supernova modeling.

Findings

Dineutrons and tetraneutrons are more abundant than deuterons at 100 ms post-bounce.

Their presence alters the neutron, proton, deuteron, and helium mass fractions.

Binding energy variations have limited effects on overall composition.

Abstract

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