Light clusters in dilute heavy-baryon admixed nuclear matter

TL;DR

This paper investigates the composition of dilute nuclear matter under astrophysical conditions, highlighting the transition from light clusters to heavy baryons with increasing temperature and density, using a combination of density functional theory and chiral perturbation theory.

Contribution

It introduces a comprehensive model that includes light clusters, heavy nuclei, Δ-resonances, pions, and hyperons in nuclear matter, accounting for temperature and density effects in astrophysical environments.

Findings

Composition shifts from light clusters to heavy baryons with increasing temperature and density.

The transition occurs nearly independently of isospin magnitude.

Simultaneous treatment of light clusters and heavy baryons is crucial for astrophysics and heavy-ion physics.

Abstract

We study the composition of nuclear matter at sub-saturation densities, non-zero temperatures, and isospin asymmetry, under the conditions characteristic of binary neutron star mergers, stellar collapse, and low-energy heavy-ion collisions. The composition includes light clusters with mass number $A\le 4$, a heavy nucleus ($\isotope[56]{Fe}$), the $\Delta$-resonances, the isotriplet of pions, as well as the $\Lambda$ hyperon. The nucleonic mean-fields are computed from a zero-range density functional, whereas the pion-nucleon interactions are treated to leading order in chiral perturbation theory. We show that with increasing temperature and/or density the composition of matter shifts from light-cluster to heavy baryon dominated one, the transition taking place nearly independent of the magnitude of the isospin. Our findings highlight the importance of simultaneous treatment of light clusters and heavy baryons in the astrophysical and heavy-ion physics contexts.