Stopping power of an electron gas for a slow antiproton

The screening of a slow antiproton in an electron gas is discussed as an analogy of dielectric response formulation. A simple parametric form of the dielectric function is proposed that leads to analytic expressions for the effective potential and induced hole density. The parameter is fixed via the cusp condition for the total electron density at the position of the probe charge. The stopping power is calculated by making use of the transport cross section. The results are in fair agreement with those given by a recent self-consistent calculation