A novel solution to the hyperon-puzzle in neutron stars

Abstract

Neutron stars offer a great opportunity to study highly compressed hadronic matter experimentally and theoretically. However, the so-called hyperon-puzzle arises at neutron star densities. The hyperon coexistence with other particles in compressed matter softens the equation of state and many widely-accepted models fail to reproduce precise observations of large neutron star masses. Here, we propose a novel mechanism to retain the stiffness of the high density state with hyperons by considering the explicit momentum dependence of their in-medium potentials. Our approach modifies conventional strangeness threshold conditions and generates new threshold effects on hyperons in high-density matter. We demonstrate these effects within the Non-Linear Derivative model, which incorporates baryon momentum-dependent fields based on empirical and microscopic studies. It turns out that even soft momentum-dependent strangeness fields do prohibit their populations in neutron star matter. The generic momentum dependence of strangeness potentials, as modeled by the non-linear derivative approach, is crucial for resolving the long-standing hyperon-puzzle in neutron stars.