Three-body momentum exchange in singly ionizing 2-MeV/u C6+-helium collisions

We study helium single ionization with emission of low-energy (εk<10 eV) electrons in collisions with 2-MeV/u C6+ ions. We explore, both experimentally and theoretically, longitudinal and transverse momentum distributions of the final reaction products. We present in-depth discussion of mechanisms resulting in the forward-backward asymmetry in the longitudinal spectra of emitted electrons and recoil ions. By comparing our experimental data and calculations we display clear signatures of the interaction between the projectile and the target core (the n-n interaction) for the transverse distributions of the recoil ion and projectile. For the collision system in question the n-n interaction is shown to represent an important mechanism of the momentum exchange