Medium Energy Hyperon Nucleon And Nucleon Nucleon Scattering PDF Download

Light Hypernuclei are a vital testing ground for our understanding of the Hyperon-Nucleon interaction. We have performed microscopic calculations of four and five-body hypernuclei using the Nijmegen nucleon-nucleon and hyperon-nucleon interactions. Our calculations include explicit Sigma degrees of freedom. These degrees of freedom are quite important since, in contrast to the [Delta] - N mass difference of ≈ 300 MeV, the [Sigma] resonance is only about 80 MeV above the [Lambda]. In addition, although there is no one-pion-exchange in the [Lambda]N diagonal channel, this longest-range term does contribute to the transition [Lambda]N - [Sigma]N interaction. Our variational calculations show that the A=4 spin 0 ground state binding energy is well reproduced by the Nijmegen HN integration, a one-boson exchange model fit to the available scattering data. The spin 1 excited state and the A=5 ground state are strongly underbound, however. We demonstrate the importance of the strong tensor terms of the Nijmegen model, particularly those in the transition channel, in obtaining this result. The limited data currently available for hyperon-nucleon scattering must be greatly improved in order to place reasonable constraints on the interaction. 12 refs., 3 figs., 3 tabs.