Partial-wave contributions to pairing in nuclei

TL;DR

This paper investigates how various partial waves of nuclear forces influence pairing in nuclei, revealing the significant role of non-standard channels and the dominance of T=1, J=0 pairing over T=0, J=1 in most cases.

Contribution

It provides a detailed analysis of partial-wave contributions to nuclear pairing, highlighting the importance of beyond 1S0 channels and the suppression of T=0 pairing in nuclei.

Findings

3P1 partial wave dominates additional contributions

Nuclear forces favor T=1, J=0 pairing over T=0, J=1

T=0 pairing is suppressed due to spin-orbit and repulsive channels

Abstract

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 semi-magic 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.