Hyperons in Finite and Infinite Nuclear Systems

Abstract

In this work, we shortly review the role and properties of hyperons in finite and infinite nuclear systems such as hypernuclei and neutron stars. Particularly, we describe different production mechanisms of hypernuclei, discuss some aspects of their γ-ray spectroscopy and their weak decay modes, and give a few strokes on their theoretical description. We reexamine also the role played by hyperons on the properties of neutron and proto-neutron stars with a special emphasis on the well-known “hyperon puzzle”, of which we discuss some of the solutions that have been proposed to tackle this problem. Finally, we review the role of hyperons on the cooling properties of newly born neutron stars and on the so-called r-mode instability.

Neutron Stars with Baryon Number Violation, Probing Dark Sectors

“…3.1 of Ref. [288] for a review of the literature on these subjects. 20 A new vector interaction between quarks may provide this additional stiffness.…”

“…At high densities, hyperonic degrees of freedom may emerge within the cores of neutron stars; for recent reviews on the subject, see Refs. [286][287][288]. These may also participate in BNV interactions, either among themselves or with the nucleons [262], that are, at best, poorly constrained.…”

Neutron Stars with Baryon Number Violation, Probing Dark Sectors

“…At high densities, hyperonic degrees of freedom may emerge within the cores of neutron stars; for recent reviews on the subject, see Refs. [303][304][305]. These may also participate in BNV interactions, either among themselves or with the nucleons [279], that are, at best, poorly constrained.…”

“…Of particular interest is the so-called hyperon puzzle (see, e.g., Refs. [303][304][305]). In Section 5, we noted that for heavy neutron stars, the nucleon chemical potentials become large enough that it is energetically favorable to produce strange baryons (Λ, Σ, etc.).…”

“…It has been suggested that the appearance of hyperons can be pushed to higher densities and that their contribution to the EoS can be stiffened through (1) hyperon-hyperon repulsion, or (2) three-body forces involving hyperons (or both), among other possibilities; see Section 3.1 of Ref. [305] for a review of the literature on these subjects. (We also note a recent study [440] in which the hyperon puzzle is addressed by the inclusion of dark matter within the neutron star core.)…”