Effective three-body interactions in the f [formula omitted] shell

Abstract

The contributions of effective three-body forces to the interaction energy of three particles in the 0f 7 2 shell are calculated using reaction matrix elements derived from the Hamada and Johnston potential. The results obtained by second-order perturbation theory are found to be much smaller than those obtained from phenomenological fits. An effective interaction is then derived for the 0f 7 2 shell performing a shell-model calculation for three particles in the whole 0f-1p major shell and through the use of biorthogonal states; effective three-body contributions turn out to be large, as expected from the results of phenomenological fits.