We present measurements of the ${}^{12}\mathrm{C}(p,{\gamma }_0{)}^{13}\mathrm{N}{/}^{13}\mathrm{C}(p,{\gamma }_0{)}^{14}\mathrm{N}$ S factor ratio at $E_p=160\mathrm{}\hspace{0.5em}\mathrm{keV}.$ The overall result of $0.33\pm 0.03$ is in good agreement with the value of this ratio obtained from previous experimental values of the S factors for the ${}^{12}\mathrm{C}(p,{\gamma }_0{)}^{13}\mathrm{N}$ and the ${}^{13}\mathrm{C}(p,{\gamma }_0{)}^{14}\mathrm{N}$ reactions. A value for the total S factor ratio of $S{[}^{12}\mathrm{C}(p,{\gamma }_{\mathrm{total}})]/S{[}^{13}\mathrm{C}(p,{\gamma }_{\mathrm{total}}\left)\right]=0.24\mathrm{}\pm 0.03$ is computed by correcting the ${}^{13}\mathrm{C}(p,{\gamma }_0)$ S factor for transitions to the other intermediate states. The direct + resonance model calculation of this ratio and the impact on the CNO cycle are also explored.

• Received 19 July 2001

DOI:https://doi.org/10.1103/PhysRevC.64.065804