The 14N(p,γ)15O low-energy S-factor

The N-14(p,gamma)O-15 low-energy S-factor is analyzed using the R-matrix model. We find that the g.s. contribution is less than previously reported. The S-factor is mainly given by the 6.79 MeV state contribution which is determined by its asymptotic normalization constant (ANC). Consequently, the S-factor at zero energy is lower by a factor of 1.7 compared to the values given in recent compilations. This result may affect the nucleosynthesis and time scale evolution in massive stars. New measurements of the N-14(p,gamma)O-15 cross section over a wide energy range, and especially at low energies, are highly desirable. Significant improvement could be also obtained from the ANC measurement of the 6.79 MeV state. (C) 2001 Elsevier Science B.V. All rights reserved.