Model for Resonance Enhancement of P- and T-noninvariant Effects in Neutron Reactions

摘要

We consider a simplified model for resonant neutron-nucleus interaction withcoupled channels. An analytical solution is given for two coupled channels andarbitrary neutron orbital momentum. A case of a week channel coupling,corresponding to narrow Breit-Wigner resonance, is analyzed in details. As faras the total width of a resonance coincides with the neutron width, the modelis directly appropriate only for light nuclei. We study a mixing of two narrows- and p-wave resonances by P- and P-,T-noninvariant potentials in the firstorder of perturbation theory. As an example a close-lying pair of s- and p-waveresonances of the $^{35}$Cl nucleus is considered. The favorable possibilitiesare shown to exist on thick targets for measurements beyond the resonancewidths. In particular, an interference minimum near s-wave resonance is ofinterest for P-odd neutron spin rotation on light spinless nuclei.