Fast p—He Transfer Ionization Processes: A Window to Reveal the Non-s2 Contributions in the Momentum Wave Function of Ground—State He

Abstract

It is commonly believed that the He ground-state wave function is perfectly understood, since the theoretically determined He ground-state binding energy [1,2] is in excellent agreement with high-precision experimental data [3J. In investigating the ground-state binding energy by high-resolution spectroscopy one probes, however, the wave function at the region of the maximum density at a distance close to the Bohr radius. The theoretical binding energies are obtained on the basis of a many-body approximation, such as the multiconfiguration approach (MCA) . Using variational methods, a wave function is generated that requires a huge basis of diagonal and off-diagonal matrix elements, or as in nuclear physics on-shell and off-shell states. These off-diagonal matrix elements represent highly correlated virtually excited contributions to the He ground state, which cannot be described by He independent-particle shell-model states, i.e., the lowest virtually excited p contributions for this He ground state are not the 2p states of He but are the so-called pseudostates [4–6] in the field of a nucleus with a nuclear charge larger than two. The MCA He ground-state wave function is then represented by a very long list of numbers, which account for the strength of all diagonal and off-diagonal matrix elements.KeywordsTransverse MomentumDifferential Cross SectionTransfer IonizationRecoil MomentumTuTI ProcessThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.