Single ionization of helium by 75 keV protons outside the velocity-matching regime in the parabolic quasi-Sturmian approachSergey Zaytsev, Alexander Zaytsev, Elena Kramar, Lorenzo Ugo Ancarani, Yury Popov and Konstantin KouzakovEur. Phys. J. D, 79 5 (2025) 55DOI: https://doi.org/10.1140/epjd/s10053-025-01005-x