SU(2) Chiral sigma model and the properties of neutron stars
  We discuss the {\it SU}(2) chiral sigma model in the context of nuclear matter using a mean field approach at high density. In this model we include a dynamically generated isoscalar vector field and higher-order terms in the scalar field. With the inclusion of these, we reproduce the empirical values of the nuclear matter saturation density, binding energy, and nuclear incompressibility. The value of the incompressibility is chosen according to recently obtained heavy-ion collision data. We then apply the same dynamical model to neutron-rich matter in beta equilibrium, related to neutron star structure. The maximum mass and corresponding radius of stable non-rotating neutron stars are found to be in the observational limit. 
P. K. Sahu and A. Ohnishi