F19(p,γ)Ne20 reaction rate and the puzzling calcium abundance in metal-poor stars

The $^{19}\mathrm{F}(p,\ensuremath{\gamma})^{20}\mathrm{Ne}$ reaction is the only process to break out of the CNO cycle at temperature below 0.1 GK and may serve as the origin of calcium in first generation of stars after the Big Bang. In the recent measurement, the Jinping Underground Nuclear Experiment (JUNA) obtained the rate of $^{19}\mathrm{F}(p,\ensuremath{\gamma})^{20}\mathrm{Ne}$ reaction, significantly larger than the previously recommended values. In this work, we perform the theoretical studies of the $^{19}\mathrm{F}(p,\ensuremath{\gamma})^{20}\mathrm{Ne}$ reaction using the Gamow shell model in the coupled-channel representation (GSM-CC). At temperature around 0.1 GK, the predicted rate by GSM-CC is close to the rate found by JUNA. Thus, based on GSM-CC, the break-out reaction $^{19}\mathrm{F}(p,\ensuremath{\gamma})^{20}\mathrm{Ne}$ from the CNO cycle might win over its competing reaction $^{19}\mathrm{F}(p,\ensuremath{\alpha})^{16}\mathrm{O}$, and produce enough calcium in the metal poor stars.