STRUCTURE OF THE A=3 SIGMA-HYPERNUCLEI

The structure of A=3 Sigma-hypernuclei is investigated on the basis of a central two-body BN interaction. We perform a three-body coupled-ch annel calculation by using the coupled-rearrangement-channel variation al method. The results suggest that there exist unstable bound states of S=1/2, i.e. H-3(Sigma), He-3(Sigma) and (3)(Sigma)n, due to the cha nnel coupling through the Sigma N potential which strongly admires S-3 (1), T-NN=0 and S-1(o), T-NN=1 states in the NN pair. The total isospi n T=1 is approximately a very good quantum number (greater than or sim ilar to 96%). In Sigma(3)He and (3)(Sigma)n, energies are largely affe cted by the Coulomb potential and dependent on the model of the Sigma N potential The characteristic features of the nucleus-Sigma potential are also discussed.