$S$-factor and scattering parameters from ${}^3$He + ${}^4$He $\to {}^7$Be + $\gamma$ data

Xilin Zhang, Kenneth M. Nollett, Daniel R. Phillips

We use the next-to-leading-order (NLO) amplitude in an effective field theory (EFT) for ${}^3$He + ${}^4$He $\to {}^7$Be + $\gamma$ to perform the extrapolation of higher-energy…