On properties of discrete and continuous spectrum of the Λ+4He system, and also π-meson decay of the Λ5He hypernucleus

In the framework of the method of resonating groups, the system Λ+4He has been studied. The characteristics of its bound state and of some continuum states are calculated. It is shown that the ΛN potential, which reproduces the Λ5He binding energy, the s phase of the Λ-particle elastic scattering on 4He monotonously decreases with the increase of the energy EΛα, whereas the p phase for the Jπ=3/2- state shows a weak resonance behavior. Other phases in the energy range from 0 to 25 MeV appear to be close to zero. The π-meson decay of the Λ5He hypernucleus is as well considered. The calculated energy and angular distributions in this decay are in good agreement with the available data