Nuclear Superfluidity and Statistical Effects in Nuclear Fission

The Bardeen, Cooper, Schrieffer formalism is applied to a calculation of the mean-square projection K₀² of the angular momentum along the symmetry axis of an excited deformed nucleus. The results are compared with empirical values obtained from analysis of recent data on fission-fragment angular distributions. The comparison corroborates qualitatively the validity of this application of the BCS formalism. Quantitative optimization of the fit to experiment yields the result that the energy gap for a nucleus deformed to the fission-barrier shape is about twice as large as the same quantity at the stable shape. Implications of this result for odd-even effects in nuclear fission are discussed.