Double electron capture cross-sections by protons in collisions with He

Double electron capture (DEC) by protons from He was studied in collisions at energies in the keV regime, theoretically and experimentally. Theoretical cross-sections were calculated using the electron nuclear dynamic approach and a binomial distribution method in the energy range 1-100 keV. Experimental cross-sections were measured by means of the grow-rate method in the energy range of 4-10 keV. The cross-sections measured are consistent with those of the previous data at the high energies of the measured interval and show a different trend for the low energy. This behavior is consistent with those of other DEC cross-sections measured by protons from He-like targets. With the two collision models, it is proven that the reference data for this system are consistent only with the assumption of uncorrelated electrons and with independent target-projectile nuclei dynamics.