Speaker
Description
Radiative $\alpha$ capture on $^{12}$C, $^{12}$C($\alpha$,$\gamma$)$^{16}$O, is studied within the framework of cluster effective field theory (EFT). We constructed a low energy EFT for the $^{12}$C($\alpha$,$\gamma$)$^{16}$O reaction and studied the related reactions to fix the parameters of the reaction amplitudes and estimate the astrophysical $S$ factors of $^{12}$C($\alpha$,$\gamma$)$^{16}$O at the Gamow-peak energy, $E_G=0.3$~MeV; it is known that $E1$ and $E2$ transitions of $^{12}$C($\alpha$,$\gamma$)$^{16}$O are dominant because of the sub-threshold $1_1^-$ and $2_1^+$ states of $^{16}$O. The theory was applied to the studies of elastic $\alpha$-$^{12}$C scattering at low energy, $\beta$ delayed $\alpha$ emission from $^{16}$N, and the $E1$ transition of $^{12}$C($\alpha$,$\gamma$)$^{16}$O in which the $S_{E1}$ factor was deduced at $E_G$. We report the study of $E2$ transition of $^{12}$C($\alpha$,$\gamma$)$^{16}$O to estimate the $S_{E2}$ factor at $E_G$ and discuss the uncertainties of estimate of the $S$ factors at $E_G$ in the cluster EFT.
