Nuclear structure of the stable even-[Formula Presented] calcium isotopes based on new experiments and shell model calculations

In view of the striking implications of the recently measured [Formula Presented] factors for the [Formula Presented] states of [Formula Presented] and [Formula Presented] we have supplemented this study with similar measurements on [Formula Presented]. For all three isotopes we utilized the powerful technique of projectile Coulomb excitation in inverse kinematics combined with transient magnetic fields. In contrast to the positive [Formula Presented] factor values for both [Formula Presented], implying large admixtures of particle-hole configurations from [Formula Presented] core excitations, the [Formula Presented] factor of [Formula Presented], is negative. This result is in very definite disagreement with the large positive value predicted by the large scale shell model (LSSM) calculations which included [Formula Presented] shell core excitations into the [Formula Presented] shell and accounted well for corresponding [Formula Presented] results. The [Formula Presented] deduced from the remeasured [Formula Presented] lifetime is indeed substantially smaller than the corresponding value for [Formula Presented], again contrary to LSSM predictions. Both [Formula Presented] and [Formula Presented] in [Formula Presented] can be explained by full [Formula Presented] shell model calculations using the FPD6 interaction without invoking core excitations.