Determine the role of the s-wave interaction in p-wave halo models

Determine whether the s-wave neutron-core interaction can be neglected in three-body systems containing a weakly bound or resonant p-wave neutron-core state, or whether it should instead be rescaled by an additional factor, thereby establishing the reliability of the Gaussian potential model for p-wave halo nuclei.

Background

The paper uses a shallow s-wave Gaussian neutron-core interaction to characterize universal behavior in two-neutron halo nuclei, while noting that realistic neutron-core interactions may contain Pauli-forbidden states, higher partial waves, and core-excitation effects. The authors explicitly restrict their analysis to s-wave halo nuclei because the applicability of the Gaussian representation to p-wave halos is unresolved.

For p-wave halos, the authors point out that a weakly bound or resonant p-wave neutron-core state generated with the same interaction strength implies a deeply bound Pauli-forbidden s-wave state. It is therefore unresolved whether the s-wave channel should be omitted from the three-body calculation or retained with a phenomenological rescaling, which would introduce an additional model parameter.

References

In general, the reliability of the Gaussian potential model for $p$-wave halos is not clear, since the presence of a weakly bound or resonant $p$-wave NC state implies the presence also of a deeply-bound Pauli-forbidden $s$-wave state, if the same strength is used. It is a priori not known, whether the $s$-wave interaction could be neglected in the three-body system, or perhaps should be scaled by some factor, thereby introducing an additional parameter.

— Gaussian characterization of two-neutron halo nuclei  (2609.19997 - Deltuva et al., 17 Sep 2026) in Section 5, “Limitations of the Gaussian representation”