Λ-N Interaction and the Structure of $^{4}_{\Lambda }He$, $^{4}_{\Lambda }H$, $^{4}_{\Lambda }He$ and $^{4}_{\Lambda }H$

Abstract

The purpose of this paper is to study the Λ-N interaction by using the meson exchange theory. We have considered four processes:l) Single K meson exchange, 2) Single η and single ω meson exchange, 3) Box diagrams of 2π and πρ exchanges with the intermediate states of ΣN, and 4) Box diagrams of 2π and πρ exchanges with the intermediate states of ΣΔ. For simplicity, the zero initial momentum approximation and the closure approximation have been taken in the calculation. The results are reasonable and consistent with experimental data. Especially for the cases of and , the theoretica1 spectra of and are in good agreement with experimental data.

A Λ–N Potential

“…The method of deriving the A-N meson exchange potential is the same as that developed in Ref. [3]. Here we only clarify some of important points on the complete A-N potential: i).…”

“…For the OBE parts besides single K,n and w considered in Ref. [3], single n' and $ meson exchanges are also included., while for the TBE parts,only the box diagrams of 2TT and Tip exchanges with the intermediate states of two particles (£N and IA) are considered.…”

“…But for some cases there are no measured values. In these cases we take them according to the SU(6) quark model [3] After the coupling constants are determined, it is easy to express the potentials by figures. Now v:e discuss the main features of TBE potentials with the help of the figures.…”

“…In Ref. [3], we derived a A-N potential from the meson exchange theory, which includes the K,n ,U),2TT,vp meson exchanges. To study the charge symmetry breaking in the A-N interactions, we considered the mass differences among K* and K°; TT* and IT 0 ; p* and p" ;l ± and £ °; A ++ » A + » A 0 and A".…”

“…To this end, we add n'» <t> meson exchange potential and a short range phenomenological core to the A-N meson exchange potential given in Ref. [3]. In Sec.II, this complete A-N potential is given and its main features are discussed.…”