First in-beam \ensuremath{\gamma}-ray spectroscopy study of $^{24}\mathrm{Al}$ and its implications for the astrophysical $^{23}\mathrm{Mg}$($p,\ensuremath{\gamma}$)$^{24}\mathrm{Al}$ reaction rate in ONe novae

Rapid Communication

First in-beam γ-ray spectroscopy study of ${}^{24}{Al}$ and its implications for the astrophysical ${}^{23}{Mg}$ ( $p, γ$ ) ${}^{24}{Al}$ reaction rate in ONe novae

G. Lotay, P. J. Woods, D. Seweryniak, M. P. Carpenter, N. Hoteling, R. V. F. Janssens, D. G. Jenkins, T. Lauritsen, C. J. Lister, A. Robinson, and S. Zhu

Phys. Rev. C 77, 042802(R) – Published 28 April 2008

Abstract

The first in-beam γ-ray spectroscopy study of ${}^{24}{Al}$ is presented. A complete level structure of ${}^{24}{Al}$ incorporating all states below the proton-emission threshold, has been constructed. The first excited state above the proton threshold has also been identified as a $3^{+}$ state at 2345.1 ± 1.4 keV. This state, corresponding to a resonance energy of 473 ± 3 keV, has been suggested to be the dominant resonance contributing to the ${}^{23}{Mg}$ ( $p, γ$ ) ${}^{24}{Al}$ stellar reaction rate. The improved precision of the level energy and unambiguous assignment of the state has reduced the uncertainty of the ${}^{23}{Mg}$ $(p, γ)$ ${}^{24}{Al}$ stellar reaction rate, which constrains the production of $A > 20$ nuclei in ONe novae.