Is e+e- pair emission important in the determination of the 3He+4He S factor? -: art. no. 055801

We show that the cross section for direct E0 pair emission is related to the cross section for direct E2 photon emission, and is a negligible contribution to the total capture cross section for He-3+He-4-->Be-7. E0 resonance emission, E1 pair emission, and internal conversion are also negligible. Thus there cannot be significant contributions to the He-3+He-4-->Be-7 capture cross section at low energies from electromagnetic emission processes other than single photon emission.