Comment on Constraints on the Low-Energy E1 Cross Section of 12C(alpha,gamma)16O from the Beta-Delayed Alpha Spectrum of 16N

Abstract

We dispute the alteration by Azuma et al. of the energy calibration of the Mainz('71) data on the beta-delayed alpha-particle emission of ${}^{16}N$ as well as the very justification of the recalibration. We use the unaltered data to observe a pronounced disagreement between the TRIUMF('94) and Mainz('71) data sets on both the high and low energy sides of the primary peak (at 2.36 MeV) of the ${}^{16}N$ alpha-spectrum. We cannot support the dismissal of the Mainz('71) spectrum by the TRIUMF collaboration and emphasize the need to include it in R-matrix fits. We discuss the need for new improved data to resolve this disagreement and its implication for the extracted p-wave astrophysical S-factor of the ${}^{12}C(\alpha ,\gamma {)}^{16}O$ reaction.

Comments: 2 figures, Shortened manuscript to comply with PRC length requirements