Fine-tunings in radiative $α$-particle capture on $^{12}$C at astrophysical energies
We investigate the fine-tuning of radiative alpha-particle capture on carbon, $α(^{12}{\rm C},^{16}{\rm O})γ$, at astrophysical energies. Utilizing results from cluster effective field theory for this reaction, we find that the low-energy data of the astrophysical S-factor allow for only very small variations in the electromagnetic...