Study of the Thomas peak in electron capture

Abstract
A joint theoretical-experimental study of the Thomas peak in electron capture by several-MeV protons on hydrogen and on He is presented. The folding of theoretical cross sections with the experimental angular resolution, required to compare theory to experiment, is explained and illustrated. Strong-potential Born calculations, with and without the full peaking approximation, are presented and compared to observation. Also compared are recent continuum-distorted-wave calculations of Salin and Rivarola.