R-matrix analysis of ^{16}O compound nucleus reactions

Background: Over the past 60 years, a large amount of experimental nuclear data have been obtained for reactions which probe the 16O compound nucleus near the α and proton separation energies, the energy regimes most important for nuclear astrophysics. Difficulties and inconsistencies in R-matrix fits of the individual reactions prompt a more complete analysis. Purpose: Determine the level of consistency between the wide variety of experimental data using a multiple entrance/exit channel R-matrix framework. Using a consistent set of data from multiple reaction channels, attain an improved fitting for the 15N(p,γ0)16O reaction data. Methods: Reaction data for all available reaction channels were fit simultaneously using a multichannel R-matrix code. Results: Over the wide range of experimental data considered, a high level of consistency was found, resulting in a single consistent R-matrix fit which described the broad level structure of 16O below Ex=13.5 MeV. The resulting fit was used to extract an improved determination of the low-energy S factor for the reactions 15N(p, γ)16O and 15N(p, α)12C. Conclusion: The feasibility and advantages of a complete multiple entrance/exit channel R-matrix description for the broad level structure of 16O has been achieved. A future publication will investigate the possible effects of the multiple-channel analysis on the reaction 12C(α, γ)16O.