On the Λ-nucleon force and the binding energy of the light hyperfragments

Abstract

The problem of the binding of a Λ-particle in nuclear matter is considered, assuming that the force acting between Λ and nucleon is due not only to the K-field but also to the π-field; the interaction schemes are:\(\Lambda \to N + \bar K, N \to \Lambda + K, N + \pi , \Lambda \leftarrow \to \Sigma + \pi \). The calculations are done assuming the d’Espagnat and Prentki hamiltonian, with both scalar and pseudovector coupling (spin of the Λ and the Σ equal 1/2). A good fit to the experimental values for the binding energy of the Λ in light hyperfragments is obtained, if one assumes that the interaction constants for both the π and K-forces are of the same order of magnitude as the coupling constant of the ordinary nuclear forces: with this assumption the π-force turns out to be the more important for the binding.