Proton and antiproton energy losses in a solid target: an exact trial potential approach

In a binary collision approach we calculate the energy loss of antiprotons and protons in a fully degenerate electron gas target, within a trial potential model which includes a velocity-dependent screening length determined through the Friedel sum rule. The results of these nonlinear calculations are compared with those obtained from the second order Born approximation (Barkas effect). For low energy antiproton and proton stopping powers, the numerical results based on this approach agree reasonably well with some recent experimental data.