Pion Double Charge Exchange in the Resonance Region
1989
18 pages
Published in:
- Phys.Rev.C 40 (1989) 2745-2762
Citations per year
Abstract: (APS)
We examine the model dependence and nuclear-structure sensitivity of several Δ33-dominated processes contributing to pion double charge exchange on nuclei in the region of the Δ33 resonance. These processes include the Δ33-nucleon interaction VNΔ and sequential scattering, in which the pion undergoes single charge exchange on two different nucleons. In all cases, the scattering takes place through the exchange of an intermediate π and ρ meson. Sequential-mediated double charge exchange is found to be only moderately sensitive to short-range correlations, meson-nucleon form factors, and the rho meson, whereas VNΔ-mediated double charge exchange is very sensitive to all these effects. Results are given for double charge exchange on O18 (double isobaric analog transitions) and O16 (nonanalog transitions). Sequential double charge exchange is shown to favor non-spin-flip matrix elements of the transition operator whereas VNΔ-mediated double charge exchange favors spin-flip matrix elements. The energy dependence of the zero-degree cross sections for VNΔ and sequential scattering are also different: Sequential tends to increase monotonically from 100 to 300 MeV, whereas VNΔ peaks at about 150 MeV. The delta-nucleon interaction is found likely to dominate over sequential scattering in nonanalog double charge exchange. The VNΔ is also large in analog double charge exchange, but it does not enable us to explain the anomalous behavior of the O18 differential cross sections.- pi light nucleus: nuclear reaction
- charge exchange: multiple
- oxygen
- Feynman graph
- pi nucleon: interaction
- pi: exchange
- rho(770): exchange
- Delta(1232): effect
- meson baryon: coupling
- S-matrix
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