The ${}^{14}\mathrm{N}(p,\gamma ){}^{15}\mathrm{O}$ reaction regulates the rate of energy generation in the stellar CN cycle. Because discrepancies have been found in the analysis and interpretation of previous capture data, we have measured the ${}^{14}\mathrm{N}(p,\gamma ){}^{15}\mathrm{O}$ excitation function for energies in the range $E_p^{\mathrm{l}\mathrm{a}\mathrm{b}}=155–524\mathrm{k}\mathrm{e}\mathrm{V}$. Fits of these data using $R$-matrix theory yield a value for the $S$ factor at zero energy of $1.68\pm 0.09(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\pm 0.16(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\mathrm{k}\mathrm{e}\mathrm{V}\mathrm{b}$, which is significantly smaller than the previous result. The corresponding reduction in the stellar reaction rate for ${}^{14}\mathrm{N}(p,\gamma ){}^{15}\mathrm{O}$ has a number of interesting consequences, including an impact on estimates for the age of the Galaxy derived from globular clusters.

• Received 23 March 2004

DOI:https://doi.org/10.1103/PhysRevLett.94.082503