Projectile-electron loss in collisions with hydrogen at relativistic impact energies

We consider electron loss from hydrogen-like projectiles in elastic and inelastic collisions with atomic hydrogen target. The projectiles move at relativistic velocities v and have atomic numbers Zp which are not very high (Zp ≪ v). In the elastic collision mode, where the target remains in the ground state, the projectile electron is removed by the interaction with both the target electron and the target nucleus. The inelastic collision mode, in which the target is excited or ionized, is governed by the electron-electron interaction and gives more than 50% of the target contribution to the total loss cross section. Within this mode the loss cross section is dominated by collisions in which the target gets ionized. At sufficiently high impact energies both the elastic and inelastic contributions to the loss cross section become independent of the energy.