The question of the origin of the missing M2 strength in sup12C is examined. A large scale shell model calculation of 2sup- states and their decay is presented. It indicates that the role of 2p-2h correlations is probably the most important in explaining the M2 quenching and that the two-body spin-orbit force is instrumental in inducing such a quenching. The role of the tensor force as well as of the Δ-N excitations remains fairly modest.

• Received 20 March 1985

DOI:https://doi.org/10.1103/PhysRevC.32.323