PARTICLE MIXING AND CHARGE ASYMMETRIC LAMBDA-N FORCES

The charge asymmetric effect of particle mixing on the 4ΛHe-4ΛH binding energy difference ΔBΛ is reviewed. It is found that Σ0 Λ electromagnetic mixing dominates the charge asymmetric ΛN potential in the s-wave and in particular ρ-exchange gives the largest contribution to ΔBΛ. In a two-body (Λ + core nucleus) model of the hypernuclei ΔBΛ is calculated to be ≈180 keV, about one-half of the experimental value. The spin dependence of the derived ΛN potential predicts that the ΔBΛ* of the first excited states is small. © 1979.