Origin of strong cutoff dependence of the Λ single-particle potential at high densities

Determine the origin of the pronounced sensitivity of the Λ single-particle potential UΛ(pΛ = 0) to the regulator cutoff ΛF at higher densities of symmetric nuclear matter when computed within the relativistic Brueckner–Hartree–Fock framework using leading-order covariant chiral hyperon–nucleon and nucleon–nucleon interactions.

Background

The paper computes the Λ single-particle potential UΛ(pΛ = 0) as a function of density in symmetric nuclear matter using leading-order covariant chiral hyperon–nucleon and nucleon–nucleon forces within the relativistic Brueckner–Hartree–Fock (RBHF) framework. The results show weak cutoff dependence at lower densities but a strong dependence on the cutoff ΛF at higher densities.

This pronounced cutoff sensitivity at higher densities introduces significant theoretical uncertainty and contrasts with the weaker dependence at lower densities. Understanding its origin is important for assessing the reliability of RBHF predictions with covariant chiral interactions and for guiding improvements such as higher-order corrections or refined regularization schemes.

References

In contrast, at higher densities, $U_\Lambda(p_\Lambda = 0)$ strongly depends on the momentum cutoff $\Lambda_F$. The origin of such an exacerbation of cutoff dependence remains unclear at present.

— In-medium $ΛN$ interactions with leading order covariant chiral hyperon/nucleon-nucleon forces (2501.02826 - Zheng et al., 6 Jan 2025) in Section 3 (Results and Discussions), paragraph discussing Figure 2 (Fig. \ref{ulp=0})