The "missing" 3 + state of Ne 18 and explosive F 17 ( p , γ ) burning

摘要: Wiescher, G\"orres, and Thielemann suggested that a "missing" ${J}^{\ensuremath{\pi}}={3}^{+}$ level in $^{18}\mathrm{Ne}$ should occur at ${E}_{x}\ensuremath{\approx}4.33$ MeV, only \ensuremath{\approx}410 keV above the $^{17}\mathrm{F}$+$p$ threshold. They noted this would provide an $s$-wave resonance $^{17}\mathrm{F}(p, \ensuremath{\gamma})$ reaction, greatly increasing its thermonuclear reaction rate. This, turn, have pronounced effect on production of $^{17}\mathrm{O}$ $^{18}\mathrm{O}$ explosive stellar environments. We searched for using $^{16}\mathrm{O}(^{3}\mathrm{He}, n)$ reaction. High-resolution time-of-flight spectra show ${3}^{+}$ occurs ${E}_{x}=4.561\ifmmode\pm\else\textpm\fi{}0.009$ \ensuremath{\approx}230 higher than suggested. The astrophysical consequences result are discussed.