The hyperon neutron star mean field model
  In this paper the impact of the strength of hyperon-nucleon and hyperon-hyperon on the maximum neutron star mass is shown. The strong hyperon-hyperon coupling constant together with the additional nonlinear meson interaction terms lead to the essential softening of the equation of state and to the existence of another more compact branch of stable neutron star configurations. The analysis of the mass-radius relations leads to the conclusion that the additional stable configurations of hyperon-rich neutron stars are characterized by the reduced value of radii. 
Ilona Bednarek, Ryszard Manka