Structure of two- and three-alpha systems in cold neutron matter

TL;DR

This paper investigates the stability and structure of two- and three-alpha particle systems within cold neutron matter, revealing conditions under which they become bound and smaller, with implications for astrophysics and nucleosynthesis.

Contribution

It introduces a novel approach using quasiparticle properties and Fermi polarons to analyze alpha systems in neutron matter, providing new insights into their binding conditions.

Findings

$^8$Be and the Hoyle state become bound at specific low densities

Alpha systems are smaller in cold neutron matter than in vacuum

Results impact models of stellar collapse and nucleosynthesis

Abstract

We present stability and structure of two- and three-alpha systems embedded in dilute cold neutron matter. By solving a few-alpha Schr\"{o}dinger equation with quasiparticle properties, i.e., effective mass and induced two- and three-alpha interactions, which are evaluated in terms of Fermi polarons, it is shown that $^8 \mathrm{Be}$ and the Hoyle state become bound at densities of about $10^{-4}$ and $10^{-3}$ of the saturation density, respectively. It is also seen that, under cold neutron matter environment, both systems become smaller than the corresponding systems in vacuum. Our results would affect astrophysical models for stellar collapse and neutron star mergers, as well as relevant reaction rates for nucleosynthesis.