Electron screening in thed+3He fusion reaction

Cross section measurements of thed(3He,p)4He reaction have been extended to an energy as low asE cm =5.4 keV. The data have an improved accuracy compared with previous work and confirm the existence of electron screening. The combined analysis of the present and previous data leads to an electron screening potential ofU e =123 ± 9 eV. A similar analysis of previous data for3He(d, p)4He leads toU e =186 ± 9 eV. Both screening potentials differ due to the molecular and atomic aggregate state of the targets involved in these investigations and are significantly larger than expected from available atomic physics models, supporting the general trend in studies of electron screening.