On the structure in the $\Lambda N$ cross section at the $\Sigma N$ threshold

Abstract

The complexity of threshold phenomena is exemplified on a prominent and long-known case - the structure in the $\Lambda p$ cross section (invariant mass spectrum) at the opening of the $\Sigma N$ channel. The mass splitting between the $\Sigma$ baryons together with the angular momentum coupling in the ${}^3{S}_1$-${}^3{D}_1$ partial wave imply that, in principle, up to six channels are involved. Utilizing hyperon-nucleon potentials that provide an excellent description of the available low-energy $\Lambda p$ and $\Sigma N$ scattering data, the shape of the resulting $\Lambda p$ cross section is discussed and the poles near the $\Sigma N$ threshold are determined. Evidence for a strangeness $S=-1$ dibaryon is provided, in the form of a deuteron-like (unstable) $\Sigma N$ bound state. Predictions for level shifts and widths of ${\Sigma }^{-}p$ atomic states are given.

arXiv comment10 pages, 4 figures

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Cited by in corpus (3)

• Hyperon-nucleon interaction in chiral effective field theory at next-to-next-to-leading order
• Test of the hyperon-nucleon interaction within leading order covariant chiral effective field theory
• Investigation of ${\Delta }^0{\Delta }^0$ dibaryon in QCD