Roles of isoscalar hyperons in probing the density dependence of the nuclear symmetry energy

W.Z Jiang

doi:10.1016/j.physletb.2006.09.020

Abstract

Abstract The role of the isoscalar hyperon Λ in probing the density dependence of the nuclear symmetry energy is studied in multi-Λ hypernuclei, hyperon-rich matter and neutron stars in relativistic models. Relationships between the properties of three types of objects and the neutron thickness in 208Pb are established with respect to the isoscalar–isovector coupling that modifies the density dependence of the symmetry energy. The exotic isotopes far from the neutron drip line can be stabilized by filling in considerable Λ hyperons. The difference of the binding energy of multi-Λ hypernuclei from different models is attributed to different symmetry energies. The isovector potential together with the neutron thickness in multi-Λ hypernuclei investigated is very sensitive to the isoscalar–isovector coupling. The large sensitivity of the Λ hyperon fraction to the isoscalar–isovector coupling occurs at about 2 – 3 ρ 0 in beta equilibrated hyperon-rich matter. In neutron stars with hyperonization, an on–off effect with respect to the isoscalar–isovector coupling exists for the neutron star radius.

Highlights

The role of the isoscalar hyperon Λ in probing the density dependence of the nuclear symmetry energy is studied in multi-Λ hypernuclei, hyperon-rich matter and neutron stars in relativistic models
The density dependence of the symmetry energy has been extensively explored through the inclusion of the isoscalar-isovector coupling terms in relativistic mean field (RMF) models[6, 7, 8, 13]
Through heavy-ion collisions it may possibly create an environment which is favorable to the formation of metastable exotic multihypernuclear objects (MEMOs) such as multi-Λ hypernuclei

Summary

Introduction

The role of the isoscalar hyperon Λ in probing the density dependence of the nuclear symmetry energy is studied in multi-Λ hypernuclei, hyperon-rich matter and neutron stars in relativistic models. It is the aim to constrain the density dependence of the symmetry energy through the investigation of properties of multi-Λ hypernuclei, hyperon-rich matter and neutron stars with hyperonization. We will perform the investigation in RMF models considering the isoscalar-isovector coupling terms that soften the symmetry energy at large densities.

Results

Conclusion