Effect of inelastic coupling on 0+ analog transitions

A comparison is made between experimental cross sections for the (p,n) reaction to the ground-state analogs of the isotopes Mo92, Mo98, Mo100, and coupled-channel calculations including coupling to the 2+ and 3- inelastic states and their analogs. When the coupling is included, very good fits are obtained for the (p,n) 0+ analog differential cross section using uniform optical parameters for all three isotopes. Experimentally observed variations of about 50% in σ(N-Z), which in distorted-wave Born approximation changes by only 10%, are explained by the coupling. A crude third-order distorted-wave Born approximation model is developed which shows that the three-step amplitudes 0+ → 2+ → 2+ analog → 0+ analog, 0+ → 2+ → 0+ → 0+ analog, and 0+ → 0+ analog → 2+ analog → 0+ analog are all in phase and are destructive to the dominant one-step 0+ → 0+ analog amplitude. NUCLEAR REACTIONS Mo92, Mo98, Mo100(p,n); measured 2+, 3- analog cross sections at 18, 22, 26 MeV; 0+, 2+, and 3- analog σ(θ) at 16 and 26 MeV calculated including coupling to inelastic channels.