Fully differential cross sections for ionization of H(2s) atoms by proton and antiproton impact

Abstract

The fully differential cross sections (FDCSs) for ionization of hydrogen atoms, being initially in the 2s excited state, by proton and antiproton impacts are calculated in the framework of the second Born approximation. The closure relation is employed to perform the summation over the intermediate states in the second Born approximation. The calculations are performed for emission of the electron in both scattering and perpendicular planes. The dependence of calculations on the projectile’s charge is investigated at different impact energies and at small scattering angles where the significant contribution to the total cross section originates. It is noticed that the influence of the electric projectile’s charge on the FDCSs in the perpendicular plane is much greater than it is in the scattering plane, and it increases as the scattering angle decreases. Finally, we calculate the doubly differential cross section (DDCS) for proton-induced reactions.