Medium effects in hyperonic interactions at neutron stars densities

Medium effects, which can be introduced as density-dependent or three-body hyperonic forces, are an essential part of describing hypernuclear interactions. In neutron stars, these effects are especially important due to the extremely high densities. Known Skyrme parametrizations of [Formula: see text]-interaction with parameter [Formula: see text] in dependence on [Formula: see text], where [Formula: see text] is the nucleon density, provide a softer equation of state and smaller masses of neutron stars than those with [Formula: see text]. However, we show that the stiffness of the equation of state depends not so much on the value of [Formula: see text] as on the interplay between different terms of Skyrme potential. We also compare density-dependent [Formula: see text] forces with the three-body [Formula: see text] forces, and show that the last implies a kind of charge symmetry breaking effect existing only in many-body systems. Finally, we insert a density dependence to the [Formula: see text] potential within the Skyrme formalism for the first time and compare the obtained potential with known potentials of [Formula: see text]-interaction.