Partial-wave contributions to pairing in nuclei

We present a detailed study of partial-wave contributions of nuclear forces to pairing in nuclei. For $T=1,J=0$ pairing, partial waves beyond the standard ¹S₀ channel play an interesting role for the pair formation in nuclei. The additional contributions are dominated by the repulsive ³P₁ partial wave. Their effects, and generally spin-triplet nuclear forces between paired nucleons, are influenced by the interplay of spin-orbit partners. We explore the impact of including partial waves beyond the ¹S₀ channel on neutron-neutron pairing gaps in semimagic isotopic chains. In addition, we show that nuclear forces favor $T=1,J=0$ over $T=0,J=1$ pairing, except in low-j orbitals. This is in contrast to the free-space motivation that suggests the formation of deuteron-like $T=0$ pairs in $N=Z$ nuclei. The suppression of $T=0$ pairing is because the ³S₁ strength is distributed on spin-orbit partners and because of the effects of the repulsive ¹P₁ channel and of D waves.