Narrow Results

In the study of nuclear matter it is common to employ effective models, that in essence are relativistic mean-field theories based on the Yukawa formulation. In such models we consider the baryons interacting through scalar and vector mesons exchanges, without taking into account the presence of quarks and gluons. The intensity of the effective interaction carried on by mesons is regulated by effective coupling constants which must be selected so that the theory is able to reproduce the basic properties of nuclear matter. The present investigation is a first approach on the analysis and explicitness of the effects of the hyperon-meson coupling constants on the prediction of measurable quantities. The purpose is to use an effective generalized derivative-coupling model and parametrize the equation of state (EoS) as a function of the coupling constants. We show the stiffness dependence of the EoS on the couplings and the related phenomenological results for the mass radius ratio of neutron stars. From observations one may constrain validity regions for the hyperon couplings.