Possible Role ofΛNNForces in Hypernuclei

The effect of a repulsive three-body $\Lambda \mathrm{NN}$ force on the $\Lambda -N$ scattering lengths and the ${}_{\Lambda }{}^{}{}_{}{}^{}\mathrm{He}_{}^4{}_{}{}^{}-{}_{\Lambda }{}^{}{}_{}{}^{}\mathrm{H}_{}^4{}_{}{}^{}$ binding-energy difference is considered. It is found that a suitable three-body force strength needed to adjust the $\Lambda -N$ scattering lengths to the measured $\Lambda -p$ ones reduces substantially the additional Coulomb repulsion in ${}_{\Lambda }{}^{}{}_{}{}^{}\mathrm{He}_{}^4{}_{}{}^{}$. Some remarks are made concerning the charge-symmetry-breaking components of the $\Lambda -N$ interaction.