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.

10 pages, 4 figures

References in corpus (6)

• Hyperon-nucleon interactions - a chiral effective field theory approach
• Explaining the Many Threshold Structures in the Heavy-Quark Hadron Spectrum
• Threshold hyperon production in proton-proton collisions at COSY-11
• The energy dependence of the pp->K+ n Sigma+ reaction close to threshold
• The pp->K+ n Sigma+ reaction near threshold
• First Model-Independent Measurement of the Spin Triplet $p\Lambda$ Scattering Length from Final State Interaction in the $\vec{p}p\to p{K}^{+}\Lambda$ Reaction

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