Abstract
The abundance of light nuclei and hyperons, that are produced in stellar environments such as supernova or binary mergers, is calculated within a relativistic mean-field model with density dependent couplings in low-density matter. Five light nuclei are considered, together with three light hyper-nuclei. We show that the presence of hyperons shifts the dissolution of clusters to larger densities, and increases the amount of clusters. This effect is larger the smaller the charge fraction, and the higher the temperature. The abundance of hyperons is also affected by the cluster formation: neutral and positively charged hyperons suffer a reduction, and the negatively charged ones an increase. We also observe that the dissolution of the less-abundant clusters occurs at larger densities due to smaller Pauli-blocking effects. Overall, hyper-nuclei set in at temperatures above 25 MeV, and depending on the temperature and chemical composition, they may be more abundant than $\alpha$-particles, or even more abundant than other heavier clusters.
Highlights
Light nuclei are found in core-collapse supernova matter and in binary neutron star (NS) mergers
In the present section we discuss how the presence of light clusters affects the abundances of heavy baryons at low densities and temperatures T 50 MeV, and two different charge fractions, YQ = 0.1 and 0.3
Tc ≈ 15 MeV, we do not expect the presence of heavy clusters, so, and as mentioned in the previous Sections, we consider 5 light clusters, 2H, 3H, 3He, 4He and 6He, which were measured by INDRA
Summary
Light nuclei are found in core-collapse supernova matter and in binary neutron star (NS) mergers. The formation of light clusters at much smaller temperatures, of the order of 5 to 12 MeV, but larger densities, below 0.1 fm−3, has been measured by the multi-detectors NIMROD at the Texas A&M University [5] and INDRA [6] at GANIL These last measurements can help understand the low-density nuclear matter equation of state (EoS) at temperatures and densities of interest to the evolution of supernovae and binary neutron star mergers. [15], introduces the temperature-dependent cluster binding shifts determined from a quantum statistical approach to nuclear matter in thermodynamic equilibrium [24,25,26,27] This model was recently improved, by taking into account continuum correlations, and it was applied to simulations of core-collapse supernovae [8].
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