Properties of strange hadronic matter in bulk and in finite systems

Abstract

The hyperon-hyperon potentials due to a recent SU(3) Nijmegen soft-core potential model are incorporated within a relativistic mean field calculation of strange hadronic matter. We find considerably higher binding energy in bulk matter compared to several recent calculations which constrain the composition of matter. For small strangeness fractions (f S < ∼ 1), matter is dominated by N ΛΞ composition and the calculated binding energy closely follows that calculated by using the hyperon potentials of our previous calculations. For larger strangeness fractions (f S > ∼ 1), the calculated binding energy increases substantially beyond any previous calculation due to a phase transition into N ΣΞ dominated matter. We also compare bulk matter calculations with finite system calculations, again highlighting the consequences of reducing the Coulomb destabilizing effects in finite strange systems.

Application of the density dependent hadron field theory to neutron star matter

“…For this reason we neglect the explicit contributions from the σ s and φ meson in our calculations. In addition, it should be noted that the contribution from these hidden-strangeness mesons can not be fixed by experimental data, introducing additional ambiguities in the model as seen in [40].…”

“…For this reason we restrict our discussion to the negative potential value. The Ξ nuclear interaction also exhibits large uncertainties with potential depths ranging from −14 MeV to −28 MeV in some investigations [40].…”

Phenomenology of K− atoms and other strange hadronic atoms

“…This means that Ξ hyperons together with nucleons and Λ hyperons may become stable against strong-interaction baryon emission, and multistrange nuclei with large strangeness fraction −S/A ∼ 1 and small charge fraction |Q|/A ≪ 1/2, decaying only weakly, should generallly exist; for a recent update see Ref. [40].…”

Strange exotic states and compact stars

“…[18] and references therein). In particular Λ hypernuclei have been studied extensively experimentally and theoretically and attractive optical potentials of U(Λ) ≈ 30 MeV have been extracted from hypernuclear data.…”

“…In fact, we find that the presence of Θ + leads to an overall reduction of the maximum mass of compact stars, similar to the case of hyperons, so that such constraints can be derived. We consider the relativistic mean-field model with nucleons, leptons and hyperons, where the interaction is mediated by the exchange of scalar (σ, σ * ) and vector mesons (ω, ρ, φ) using SU(6) symmetry relations for the coupling constants of the vector mesons and adjusting the potential depth with the scalar coupling constants appropriately [31,32,33,18]. The coupling constants for pentaquarks are chosen similarly.…”