$^{14}$N(p,$\gamma)^{15}$O $S$ factor and the puzzling solar composition problem

TL;DR

This study uses a microscopic theoretical model to analyze the $^{14}$N(p,$ ext{γ})^{15}$O reaction, crucial for stellar processes, achieving good agreement with experiments but highlighting discrepancies in solar neutrino predictions.

Contribution

The paper introduces a GSM-CC microscopic approach to model the $^{14}$N(p,$ ext{γ})^{15}$O reaction, providing insights into its astrophysical $S$-factor and implications for solar composition.

Findings

Good agreement with experimental $S$-factor data for total and partial contributions.

Predicted zero-energy $S$-factor exceeds experimental values.

Derived abundances match recent measurements but are lower than solar neutrino observations.

Abstract

In stellar hydrogen burning, the CNO cycle dominates, with the $^{14}$N(p,$\gamma)^{15}$O reaction being the slowest process. Consequently, this reaction critically influences the solar composition, CNO neutrino fluxes, and the evolution of star clusters and galaxies. Recent direct measurements of $^{14}$N(p,$\gamma)^{15}$O have reported an enhanced astrophysical $S$-factor. This work presents a microscopic theoretical study of the $^{14}$N(p,$\gamma)^{15}$O reaction using the Gamow shell model in the coupled-channel representation (GSM-CC). The calculations achieve good agreement with experimental data for both the total $S$-factors and the separate contributions from transitions to the ground state and excited states of $^{15}\mathrm{O}$. However, the predicted $S$-factor at zero energy exceeds the experimental value. Based on the computed $S$-factors, the derived carbon and nitrogen abundances align closely with predictions from recent $^{14}$N(p,$\gamma)^{15}$O cross-section measurements, yet remain significantly lower than the latest solar neutrino observation values.