$(I,J^P)=(1,1/2^+)$ $\Sigma NN$ quasibound state

TL;DR

This paper reviews theoretical models and Faddeev calculations suggesting a quasibound $ ext{Sigma} NN$ state with specific quantum numbers, aligning with recent experimental indications of such a resonance.

Contribution

It provides a theoretical analysis of the $ ext{Sigma} NN$ system using symmetry-based hyperon-nucleon interactions and Faddeev calculations, supporting the existence of a quasibound state.

Findings

Faddeev calculations indicate a $ ext{Sigma} NN$ quasibound state near threshold.

Calculated pole position at 2.92 - i 2.17 MeV agrees with experimental data.

Theoretical models support recent experimental hints of the resonance.

Abstract

JLab has recently found indications of the possible existence of a $\Sigma NN$ resonance at $(3.14 \pm 0.84) - i (2.28 \pm 1.2)$ MeV. In the past, using models that exploit symmetries between the two-baryon sector with and without strangeness, hyperon-nucleon interactions have been derived that reproduce the experimental data of the strangeness $-1$ sector. We make use of these interactions to review existing Faddeev studies of the $\Lambda NN$-$\Sigma NN$ system that show theoretical evidences about a $(I,J^P)=(1,1/2^+)$ $\Sigma NN$ quasibound state near threshold. The calculated position of the pole is at 2.92$\,-i\,$2.17 MeV, in reasonable agreement with the experimental findings.