THE Z(1)(3) CORRECTION TO THE BETHE-BLOCH ENERGY-LOSS FORMULA

Corrections to the Bethe-Bloch formula for the energy loss of charged particles in matter have been of much interest since the early work of Barkas and collaborators, who found differences between the ranges of positive and negative pions of the same energy. We here report the fi rst rigorous many-body perturbation-theoretic calculation of the Z(1)( 3) correction for a wide range of particle velocities in the electron gas, Z(1) being the projectile charge. Our calculations are in good ag reement with recent measurements of the energy loss of protons and ant iprotons.