K-equilibration in light- and heavy-ion-induced fission

Basic assumptions in statistical models of fission fragment angular distributions predict an angular variation of the fragment spins which is governed by the same parameters that control the angular distribution. This effect has been investigated in both light- and heavy-ion induced fission using γ-ray multiplicity techniques. While the multiplicities vary with angle, the effect is usually much weaker than expected. The disparity between theory and experiment is reduced significantly if the excitation of angular momentum bearing collective modes is included in the calculations. However, discrepancies still persist, suggesting a partial breakdown in the assumptions of the model