Energy Gap in Neutron-Star Matter

On exactly taking into account the attractive effect of the 3P2 - 3F2 coupling due to the two-nucleon tensor force and the effect of the one-body potential, the density region in the neutron-star matter where the 3P2-superfluid state exists is determined as ρ ≃ (2 ∼ 8) × 1014 gcm-3. The tensor coupling effect is shown to play an indispensable role on the existence of the 3P2-gap in neutron-star matter. The 1S0-gap is also investigated, leading to the result that the 1S0-superfluid state exists in the density region ρ ≃ (1.0×1011 ∼ 1.5 × 1014) gcm-3. On the basis of these results, the region ρ ≃ (1.5 ∼ 2.0) × 1014 gcm-3 is considered to result in the normal state.