Black hole scalarization with Gauss-Bonnet and Ricci scalar couplings

Spontaneous scalarization is a gravitational phenomenon in which deviations from general relativity arise once certain threshold curvature exceeded, while being entirely absent below that threshold. For black holes, known to be triggered by coupling between scalar and the Gauss-Bonnet invariant. A with Ricci scalar, can trigger neutron stars, instead not contribute onset of hole scalarization, has so far been largely ignored literature when studying scalarized holes. In this paper, we study combined effect both these couplings on scalarization. We show plays significant role properties solutions their domain existence. This work an important step construction models evade binary pulsar constraints have as cosmological late-time attractor, still predicting observations.