Study on the tidal deformabilities of neutron stars in the relativistic mean field approach with δ mesons

The research on the macroscopic properties of neutron stars has great significance for revealing the internal composition and structure of neutron stars. We have analyzed the influence of δ mesons on the equation of states, the maximum masses, the tidal Love numbers and the tidal deformabilities for the conventional neutron stars and the hyperon stars within the relativistic mean field theory. It is found that the presence of δ mesons can strengthen the tidal deformabilities of the low and medium-mass conventional neutron stars (or hyperon stars). However, the strengthening trends of the tidal deformabilities with δ mesons are gradually weakened as the increase of the masses for the conventional neutron (or hyperon stars). Especially for massive hyperon stars, the tidal deformabilities with δ mesons is weaker than the corresponding values without δ mesons. Moreover, the presence of hyperons can reduce the tidal deformabilities of stars with the same mass. For the stars containing δ mesons, only the tidal deformabilities in the hyperon stars with Λ, Σ and Ξ hyperons can satisfy both constraints of GW170817 and GW190814 events under the parameters selected in the paper. As the date on gravitational waves associated with the neutron stars gradually increase, which will provide a possible way for judging the hyperon species in the hyperon stars.