Revised Reaction Rate for the Astrophysical Reaction ¹⁸O(p, α)¹⁵N via a Global R-matrix Analysis

The 18 O( p , α ) 15 N reaction is of particular importance for influencing the abundances of key isotopes such as 19 F, 18 O, and 15 N. Peculiar abundances for these nuclei are observed from spectra or meteorite grains originating in asymptotic giant branch stars. The 18 O( p , α ) 15 N could provide a way to explain the discrepancy between the observations and model predictions. A comprehensive R -matrix analysis has been performed for the 18 O( p , α ) 15 N reaction by including additional constraints from other reaction channels; in particular, the 15 N+ α scattering data were involved in the analysis for the first time. All available data were compiled and used in the R -matrix analysis. The fitted resonance parameters are compared with previous works. A revised determination of reaction rate has been extracted, relying on the present fitting parameters. The uncertainties on the corresponding reaction rates were then obtained by a Monte Carlo analysis.