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We use the next-to-leading-order (NLO) amplitude in an effective field theory (EFT) for ${}^3$He + ${}^4$He $rightarrow {}^7$Be + $gamma$ to perform the extrapolation of higher-energy data to solar energies. At this order the EFT describes the capture process using an s-wave scattering length and effective range, the asymptotic behavior of $^7$Be and its excited state, and short-distance contributions to the E1 capture amplitude. We use a Bayesian analysis to infer the multi-dimensional posterior of these parameters from capture data below 2 MeV. The total $S$-factor $S(0)= 0.578^{+0.015}_{-0.016}$ keV b at 68% degree of belief. We also find significant constraints on $^3$He-$^4$He scattering parameters.
Antiproton scattering off $^3He$ and $^4He$ targets is considered at beam energies below 300 MeV within the Glauber-Sitenko approach, utilizing the $bar N N$ amplitudes of the Julich model as input. A good agreement with available data on differentia
Background: Theoretical calculations of the four-particle scattering above the four-cluster breakup threshold are technically very difficult due to nontrivial singularities or boundary conditions. Further complications arise when the long-range Coulo
Differential cross sections for elastic Compton scattering from $^4$He have been measured with high statistical precision at the High Intensity $gamma$-ray Source at laboratory scattering angles of $55^circ$, $90^circ$, and $125^circ$ using a quasi-m
The ${^3{rm He}}(alpha,gamma){^7{rm Be}}$ and ${^3{rm H}}(alpha,gamma){^7{rm Li}}$ astrophysical $S$ factors are calculated within the no-core shell model with continuum using a renormalized chiral nucleon-nucleon interaction. The ${^3{rm He}}(alpha,
Four light-mass nuclei are considered by an effective two-body clusterisation method; $^6$Li as $^2$H$+^4$He, $^7$Li as $^3$H$+^4$He, $^7$Be as $^3$He$+^4$He, and $^8$Be as $^4$He$+^4$He. The low-energy spectrum of each is determined from single-chan