Influences of Both Δ^- and Δ⁰ Particles on the Neutron Star Cooling

The influences of Δ quartet, especially Δ^? and Δ⁰ particles, on the neutrino scatting and cooling properties of neutron stars are discussed. The results show that Δ quartet can change the density range of direct Urca process of nucleons for muons, as well as the neutrino emissivity and luminosity. The role of Δ on the cooling rates is complicated. It is found that Δ quartet slows the neutron star cooling obviously in hyperonic neutron star matter. However in nuclear matter, Δ can not influence the cooling too much, unless the neutron star is quite massive. The Δ-meson coupling constants can also impact on the results, and the relatively smaller value, the stronger effects of Δ quartet.