First direct measurement of the ${}^{11}$C($\hat{I}\pm$, p)${}^{14}$N stellar reaction by an extended thick-target method

Abstract

The ${}^{11}$C($\hat{I}\pm$, p) reaction is an important $\hat{I}\pm$-induced reaction competing with ${\hat{I}}^2$-limited hydrogen-burning processes in high-temperature explosive stars. We directly measured its reaction cross sections both for the ground-state transition ($\hat{I}\pm$, $p_0$) and the excited-state transitions ($\hat{I}\pm$, $p_1$) and ($\hat{I}\pm$, $p_2$) at relevant stellar energies 1.3 - 4.5 MeV by an extended thick-target method featuring time of flight for the first time. We revised the reaction rate by numerical integration including the ($\hat{I}\pm$, $p_1$) and ($\hat{I}\pm$, $p_2$) contributions and also low-lying resonances of ($\hat{I}\pm$, $p_0$) using both the present and the previous experimental data which were totally neglected in the previous compilation works. The present total reaction rate lies between the previous ($\hat{I}\pm$, $p_0$) rate and the total rate of the Hauser-Feshbach statistical model calculation, which is consistent with the relevant explosive hydrogen-burning scenarios such as the $\hat{I}½p$-process.

8 pages, 8 figures, final version as submitted to Physical Review C for publication after peer-review